kaylee34

1998 4runner 5VZE 3.4L, auto, 4WD 193,000 miles.
I need some help please guys. This is my baby and daily driver. She's been down for two weeks now and I'm at a loss. I've searched and followed everything similar I can find on here with no luck so far. I apologize for the long read.

History:
Running like a champ, not a problem in the world, all maintenance done on time.
New drive belts about 5000 miles ago. Alternator good, battery recently replaced.
Timing belt, water pump, pulleys & all done in late August.
Doesn't lose oil or coolant, maybe a little valve chatter but I expect that.

Got down to about 1/4 tank of gas one night and stopped to fill up. Drove EXACTLY 18 miles home, to work the next day and to dinner. Ran smooth as glass. Felt a bit of a jerk pulling into the parking spot at dinner but I wasn't sure. Left dinner, made it out of the parking lot to the light and the tach began jumping. Surging up to 1400 rpm, dropping to about 300, back to 1400 then back to normal ~700 idle. It did this twice then dropped back off and died. Truck was warm but not up to full operating temp. Restarted immediately (usual 3-4 cranks) and repeated the funky idle and died again. I shut her off and had it towed. I really didn't want to have it quit in the middle of a busy intersection. NO CEL.

Mechanic at the shop couldn't find anything obviously wrong. No codes active or stored, no CEL. Funky idle did show itself. Starts and runs fine when cold. As it warms up, there's a slight whining noise to be heard and the idle problems started manifesting. It misses, surges, bogs and dies. No apparent loss of power when he drove it around and it always fires right back up. He checked the vacuum lines, battery, tested the alternator and checked the throttle body. I had it hauled back home and started looking at obvious things.

What's been done:
Got it home and checked for codes (none) and still no CEL. Still starts & runs beautifully when cold, runs like crap warm & at temp.
Replaced power steering pump & flushed fluid with new ATF (it was on the way out)
Replaced lower idler pully (bearings were shot) and removed AC drive belt (AC was screaming and I don't need it now anyway)
I still have a whine almost like a bad PS pump but not so loud as that. The whine has not changed and started softly about mid-August.

New plugs and wires (NGK wires, proper NGK dual electrode plugs)
Cleaned air filter (K&N) and didn't over-oil (I run one on the Harley so I know to be careful)
Tested and cleaned MAF
Replaced PCV valve (it was time)
Tested TPS
Tested coil packs
Pulled throttle body, cleaned thoroughly. Linkage is working properly & butterfly looks good
Cleaned IAC valve. I found a freaking peanut in the thing! Yes, seriously, a peanut. Toasty looking sucker and I have NO idea how it got in there. Got all the carbon crud out and it's working nicely.
Injectors ticking nicely and sound the same to me at least.
Dull whine is still present & begins within 15 seconds of startup It sounds like a bad bearing and not belt squeal. I haven't been able to pinpoint it with the stethoscope.

Put it all back together. Started right up, ran at high idle at first, settled to normal range as it warmed up and randomly dropped to a slow idle ~400 rpm. Would run if I held idle to ~ 1100-1200. Cut it off & started a couple times. Got it up to operating temp and ran it through the gears to see if it would drop. Misses and stumbles at idle in park & neutral. Dies instantly shifting from neutral to reverse. Sometimes from Park to reverse but will miss in reverse. Idled fine in drive with no missing.

Finally got it to throw a code. P0300 random misfire. Cleared the code and left it alone for another few days.

Fired it up today, same thing. Starts fine, no problems when cold. Whine started right up. Got it up to operating temp. Missing returned. Ran it around the block. Missing when coming to a stop, sometimes missing when driving. Dumped a bottle of red HEET in the tank & filled up with fresh gas. Limped it 2 blocks back home. It is definitely! worse when up to temp. I also think it's lost power now but hard to tell without hitting a major road which i don't want to chance. Still NO codes and no CEL.

Any suggestions where to go from here?
Thanks much in advance! :-)

akwheeler

Wow, you are really good at the game "stump the chump". Lots of good information though, much better than "it has a funny noise". I think the best thing for you to start with is the whine, Take all of your belts off (not the timing belt) and see if the whine is still there and try to narrow down where it sounds like it is coming from, front/back/top/bottom/left/right. Also take the upper timing belt covers off and look inside, maybe you had a bearing seize up on an idler or the water pump. then check your timing marks if you still haven't found anything to point at. I hope this helps, drivability issues have never been my area of expertise.

kaylee34

LOL! Well, I'm a stumped chump for sure!

The whining noise is very disconcerting. It is RPM related and not overly loud. It's much easier to hear when sitting in the rig.
I know it's not coming from the AC, the belt is off.
Not the power steering pump but I'll pull the belt and see what happens.
Not suspecting the alternator but I'll pull that one for a few minutes too.
It does seem to be coming from the central front of the engine but that's not incredibly helpful.
I'll recheck everything inside the timing belt cover. The whine started about a week before the timing belt was done but can't hurt to make sure it's all good.

The missing and stalling is not making me happy. It's not sputtering and jumping all over the place at idle anymore but it's sure not right. When it dies, it just dies. No shake, shudder, coughing or thinking about it. The miss is more of a pause. Runs nicely -pause- runs nicely -pause- anywhere from a few seconds to a couple minutes between pauses. Worsening as it gets up to temp is making me think electrical breaking down. I'm not going to just shotgun parts at it though.

I'm going to replace all the vacuum lines. They're looking crappy anyway. Can't hurt and it's cheap.
The fuel filter needs to be replaced but it's locked up tighter than Dick's hatband and not budging *yet*.

If this was the Harley, I'd have had it fixed by now. -sigh- Yes, I love my simple carburetor.

akwheeler

From your original post I thought the noise came after the timing belt, did all of your problems start at the same time and was this all before or after the timing belt was done?

kaylee34

* New info towards end of post

akwheeler that's a VERY good question and one I can't answer 100%. It's had several noises start this summer. MOST have been related to things already addressed. The noise I still have is the one I can't isolate yet. If I had to nail it down, everything started right around the same time just before the timing belt change and became exponentially worse after the timing belt change. Details below.

I hadn't used the AC in 3 years before this summer. AC wasn't blowing cold, charged it up in late June / early July (known leak in the evaporator coil) and ran it this summer.

Noise 1 before timing belt: oscillating grinding noise = bad bearing in the AC idler pulley (replaced pulley, bearings were bad)

Noise 2 after timing belt: grinding scream near same area, louder and pitch changed when blower turned on & again when AC engaged = suspect compressor or compressor clutch, it is rusted (removed belt, noise gone)

Noise 3 ten days before timing belt change: grinding whine #1; suspect power steering pump. Fluid not black (dark red) but burnt smelling. Flushed twice. Noise gone. Burnt smell and noise returned after timing belt change. Fluid still bright red. Said screw it and replaced the pump, flushed the fluid again. Noise appears to be gone. Steering is tighter. Yes, used ATF.

Noise 4 started unknown: Slight valve tapping on #6 (not concerned about this)

Noise 5: the suspected bearing one I'm still hearing. Possibly started 10 days to 1 week before timing belt change, may have appeared after. Can not isolate this noise. Not present when cold. Becomes louder once the truck warms up and is clearly audible inside & outside the rig. Seems to be coming from the front center but possibly rear center portion of engine. May be slightly more to the passenger side. It's very hard for me to tell where it's coming from as my hearing is shot. It ALMOST sounds like a vacuum leak but not quite. There's an oscillation to it when the rig is idling ~ 450-500 rpm. Might just be easier to hear it at that speed. So very hard to say exactly when this particular noise started up.

The very obvious misfires and stalling started 2 weeks ago so after the timing belt change. It MAY have started before that as I did have 2 occasions this summer when it might have cut off on me right after starting up. I'd say cold engine when this happened (cold motor, drove 2 blocks to the store & came back out when it did this). I can't even say for sure it cut off, I might have just turned the key on & not started it. If I absolutely had to throw these two incidents into the mix as when it started, I'd blame a dirty MAF and IAC. Other than these two possibles, the misfire problems have ALL been after the timing belt change.

* Got the mechanic guys over here and ran it again tonight. Noise isn't there when cold and gradually becomes louder as the rig warms up. Heard the oscillation again. Put the live scanner on it. Ran fine cold. Idled up to temp, no missing. No codes. Took it for a drive through the neighborhood. Went 5 blocks and it died going around a corner. So dying under load. Hooked the scanner back up & drove it. LOTS of random misfires going everywhere then disappearing. Cyl 1&2 then 3&4, back to 1&2. Misfired on all but #5. Worst misfires were #1&2. Died several times. Sometimes immediately after restart, sometimes when slowing to a stop. Lost power twice but normal power most of the time. Came back home, misfiring at idle but not dying. NO CEL and codes never stayed.

I grilled the guys on the timing belt change since I had them do it for me. The crank pulley bolt was NOT torqued to spec. It's been three months and less than 1500 miles so if this is the problem and it's started walking, I'm hoping there isn't any real damage done. It's coming apart and being done again properly regardless so we'll see.

Any ideas?

akwheeler

Random misfires that come and go make me think you may have a poor connection at your engine control module, possibly power supply, they do weird things if the voltage drops a little too low. What is your battery voltage with the engine running? It's hard to see how all of these symptoms could be related. Did you try running it with NO belts on after warming up to see if the whine went away? If you suspect vacuum leaks you can often find them with an unlit propane torch or starting fluid, the starting fluid can be dangerous though. when you get near the leak the RPMs will increase. you could intentionally make a leak to try this out (if it stays running) and see how it works. With all of the noises you listed maybe you should just turn up the radio, they will eventually become easy to find! LOL!

Kolton5543

What does your scan tool say about A/F ratio. Could be a vacuum leak. Get some carb cleaner and spray around the base of the intake maifold, plenum gaskets, throttle body and any where you see a vacuum hose. If the idle changes then there's the problem. It sounds to me like you have a very lean condition on your hands. would run better cold due to the ecu enriching the mixture. When warm it leans out and gives you your problems.

kaylee34

akwheeler & Kolton, thanks guys!
Not much going to be done in the next few days. I've got pneumonia so the rig is going to have to wait a bit.

To answer questions & comment:
Yes, it's weird and I completely agree there's more than one thing going on here.
I'm with you on the poor connection somewhere. I just can't see all three coils packs crapping out at the same time nor all the injectors.
Grounds are all good and tight.
Alternator test and battery test with the live scan was OK. Alternator and battery in spec. Both are less than 2 years old BTW.
I hear you on the very lean condition too. I'm very EFI ignorant and don't understand exactly how it compensates except it's a computer. I'm learning though.
I don't recall the numbers but the scan tool showed nothing grossly out of whack on the A/F ratio.
Tried carb cleaner to find a vacuum leak with engine both cold & up to operating temp. No leak found.
Will try propane since that does tend to work better in my experience on small PITA leaks.

Once I'm feeling a bit better I will run it up to temp, check for leaks then start cutting off the remaining belts to see if that will isolate the noise some.
AC belt is off now (it's not this)
Power steering next (could be the idler pulley)
Alternator belt last.
If that doesn't find the noise, I know I'll have to dig deeper. Doesn't matter, I'm going to have to anyway.

kaylee34

Been awhile but it's time for me to come back and update this thread. It's been a long winter and working on it unfortunately had to wait too much.
The whining noise turned out to be related to the AC compressor. Suspected an idler pulley but that wasn't it. Replaced those and still had the whine. Cut the AC belt off and the whining has stopped. I'll deal with that later. I never used the AC anyway.

Truck is still having random misfires.Since there are no hard codes, just crazy pending codes jumping all over the place it's been extremely hard to diagnose. Everything so far has been testing within spec. No parasitic grounds, no problems with grounds anywhere I can find.

Fortunately I can work on it a bit at the time now. It's been a systematic and semi-expensive process of replace and test with no resolution yet.

MAF sensor is clean and tests within spec - random misfires
IAC cleaned, tests within spec and works perfectly - random misfires
New NGK plugs and wires, gap verified - random misfires
New PCV valve - it was time
New battery - might as well, it sat dead for 4 months
New Denso coil packs - random misfires
New injectors & TPS done at the same time - random misfires & high idle (1100-1400 rpm).

Suspect the high idle is due to the new TPS and the ECU having to relearn. I am not even test driving it at this point. I can swap the old one back in and see if it makes a difference. The injectors were pretty nasty looking so I don't mind replacing those.

The truck drove fine on a short (6-8 block) test drive when up to temp. No stalling, no surging, no missing at temp or on that short drive.

Had the scanner brought back over and there's still an issue somewhere. Still having random misfires beginning when the truck starts warming up. Cyl 3 is most frequent, began at 1 went to 3, bounced to 2 & 4, 5 & 6 Just all over the place quickly, no hard codes.

Next up on the list is the crank position sensor. If that doesn't fix it, it's going back to the guys that did the timing belt and I'll have them pull everything back apart.

Any other suggestions, I'm all ears.
I really NEED my truck back very soon. I'm moving 600 miles away at the end of the month and have to get this taken care of before then. :-(
Thanks everyone for all the thoughts, suggestions and help so far. It's been very, very helpful :-)

fierohink

aowRS

kaylee34

@ fierohink New old stock toyota OEM injectors. Not cheap! That hurt a little bit but I'm of the belief in do one, might as well do them all while I'm in there. It wasn't anywhere near as hard a job as I was expecting. I do think an injector going out may have been at least some of the problem. They were not pretty looking when I pulled them out. Fuel pump is good. Fresh full tank of gas with a bottle of HEET in it just in case I got bad gas at the station right before all this nonsense started. Didn't hurt with it sitting a couple months either. Fuel filter is definitely suspect. Even if that's not contributing, it needs to be done. Unfortunately, I haven't yet been able to get that stubborn bugger off. I wasn't much for laying on the ground in cold wet weather when I had pneumonia this winter but once it quits raining later this week it's getting replaced if it likes it or not. I have a bad habit of breaking tools, wringing bolts off and just generally making more work for myself than I really need to, so I really don't want to twist the fuel line to shreds.

@ aowRS super data point, thank you! Everything was original on this one as well except what needed to be done or I'm anal about. I've found these trucks to be so reliable that there's no way I'll part with this one unless I absolutely have to and then I'll be getting another. It's been to three shops so far, one I know and trust, one with a great reputation, the original shop it was towed to, and some really good backyard guys. Shops are stumped, I'm stumped, the guys are stumped. All told it's cost me a six pack of beer to the one shop, $100 diagnostic fee to the second shop & $95 diagnostic fee to the third shop. Shops have all said they have no idea. I don't know of any different shop around here to take it to and no one I know has anywhere to suggest except the one it's already been to. With no specific codes, obvious problems or even a hard P0300 code that will set, all they can suggest is wait til it breaks or throwing parts at it and hope. All told, it's spent 5 weeks in shops since this started. I'm now out of free AAA towing until September LOL! The backyard guys are nice enough to let me borrow them and their scanner when they have time for whatever deal we work out. Last night cost me a clutch cable I've had laying around for years. I'm getting off pretty cheap so far but I'd happily pay dealer rates to get my truck fixed! Fuel injection and this computerized stuff escapes me. But, I'm learning as I'm going along with it and that's always a good thing :-) I wish I'd had enough foresight last night to ask what the fuel trims and all were reading but I didn't. He didn't mention anything odd or out of normal until random codes started popping up again and that was all.

I've got an intermittent faint chirp but I'm 99% sure that's a slightly loose alternator or power steering belt since those are brand new (again) and I didn't check tension on them very carefully.

Short version of what it's doing now:
Runs smooth as glass, no surging, no bogging, no stalling under load, no obvious miss in the motor on short test drive and idling ~15 minutes a few times (something seems to be fixed, my money's on injector)
Idle cold starts at 1100 rpm in park, drops to ~ 800 in gear
Idle creeps up as the truck is warming up to 1400-1450 in park, drops to ~1100 in gear at operating temp
Random misfire codes everywhere now before up to operating temp. This is a change from before. Used to have to be up at temp, now this is starting with the temp gauge reading just above maybe 1/4 way up.

?Throttle response under load maybe sluggish. I don't have the "feel" of it anymore it's been so long. I do think the rpm's head up way quicker than it used to "before problems" while acceleration is not so responsive. If that makes sense.

(the consistent rpm difference and creeping is telling me something? very lean condition now as suggested by Kolton?) Gut feeling today is telling me to double check my work and look for a vacuum or intake leak now since that's all been monkeyed with last. It's not telling me crank position sensor but I'll swap it anyway since I have it. Gut is also telling me this really is more than one problem even though I keep "looking" for just one problem to fix.

Thanks guys for the encouragement, suggestions, thoughts and letting me write long posts to work out my own thoughts. It's much appreciated! :-)

kaylee34

Quickly addressing all those noises I mentioned in post #5 for anyone that might find this thread with a similar problem:
I strongly suspect two of the belts were switched around when the timing belt was done and that caused the problems with the PS pump, compressor, idler pulleys & weird oscillating noise # 5. If this noise (or any other) comes back after I recheck the belt tension (new slight chirp) I'll update on that also.

old87yota

When you have access to a scanner that can display live engine data, have someone experienced looking at live engine data look through ALL the data when the problems occur. They should look to see if any of the data points look out of normal values.

For example, say the scanner said the engine coolant temp for the engine was 50 degrees after it had been running for a while. You could see that this is incorrect and could investigate why the value is wrong.

Sometimes just looking through the data list can dig up that a sensor is not reporting to the computer correctly or that there may be an underlying problem that just does not throw a code. Sometimes misfire counters are not always 100% correct too.

What you need right now is a direction to go into to investigate.

Good luck!

Soumipukuu

Test your igniter while your at it, those can cause all kinds of dastardly problems, and the electronics.arent all that complicated when you look at the nice color coded diagrams from TIS, it makes it alot easier to chase things like bad grounds etc. I have all the EWDs for a 98 of you want, I'm not sure if anything changed 98-99