aerobat66

'99. 4Runner SR5. 3.4. 185,000 miles.

Long story short, I replaced one of my injectors (#4, if I recall) about 2 years and less than 10k miles ago. I know I should have done all 6, but I was unemployed at the time.

That solved my CEL and it has run fine ever since, until fairly recently. It has started idling roughly again, and I suspect either the GB remanufactured one I replaced has gone bad, or another one or more have gotten too old. Air filter, plugs and plug wires (all NGK) and fuel filter were all replaced fairly recently.

Local Toyota wants $199 per injector, and they only have one in stock. Screw that noise.

RockAuto has:

GB reman's for $40 ea, plus core.

Airtex/Wells new for $57 ea.
Standard Motor Products new for $58 ea.
Autoline "new" for $74 ea (why do new ones have a $10 core?)
Beck Arney new for $75 ea.

Has anyone actually ever used any of these, and can give me positive or negative feedback on the brands? I have no CEL codes, so I can't point to which cylinder(s) it is.

Thanks

75w90mantraN

Not an answer to your question but it wasn't mentioned about whether the MAF was cleaned? Give that a go at least. Common culprit behind rough idling. Check for vac leaks too. Cheaper things to rule out in the meantime. Depending on which injector (assuming) is actually bad, can influence your decision. If its the non OEM one, I'd prob go back. If it's an OEM that's bad, then reman. Hope that helps.

aerobat66

The MAF was cleaned about a year ago, which was probably the first time ever.

Charchee

It wasn't much of a chore was it? Go on and clean it again. My 01 had to be cleaned twice in 130K miles. It would even make it throw a misfire code on the parts store's code reader. Now I clean mine on my 02 every time I change transmission oil. Those are unrelated maintenance items, by the way. That's just the interval I chose to match.

aerobat66

Update:

I just pulled the MAF. I was hoping it was dirty, but it looked pretty clean. I sprayed it with MAF cleaner anyway.

All of my vacuum hoses look good. I remember taking care of that last time I was in there, less than 10k miles ago.

Now I feel 99% sure that I have one or more bad injectors. I have gotten some positive feedback on the Beck Arnley injectors.

I also got some positive feedback on these: https://www.fiveomotorsport.com/1999...34l-6-cylinder Anyone else ever use them?

aerobat66

Update. I just replaced all 6 injectors with remanufactured injectors from FiveOmotorsports.

I am not a happy camper. It fired right up, but immediately began idling roughly. Prior to the injector replacement, it only ran rough when it had been running a while and everything was hot.

I shut it down and looked for fuel leaks. I don't see or smell any. I triple checked that everything was reconnected. I had labeled every hose, etc. that I removed, and put everything back. I started it again and it still idled quite rough. I turned it off again, checked my work again, and then cranked it. It turned over, but nothing. I let it set a few minutes, tried again, and it runs, but still roughly.

All vacuum hoses look good. I cleaned the MAF after I initially posted this. No CEL. No fuel smell, and no fuel visible. Everything appears reconnected correctly.

I had disconnected the battery for a couple of hours while I did the replacement. Is it possible that the ECU didn't reset itself during those 2-3 hours, and is still trying to compensate for a bad injector?

I kind of suspect that one of the 2 intake manifold gaskets might be leaking, either because they got old, or maybe I dinged one while doing the work today.

Anyone ever been through this and have any ideas what I should look for?

75w90mantraN

Sorry about your frustrations.

I dont know about those injectors you got, so I cant say. Doubt they would be crap right out the box, but hopefully there's a return policy since now the truck runs worse than before.

I think the ECU would have reset once dc after awhile.

Maybe do fuel pressure check? One time it wouldn't crank...

Can't remember if you suspected a head gasket or intake leak, but you could do a compression test to check...although I would think you might be burning coolant as well if there is.

Fuel filter was changed already?

75w90mantraN

And I know the MAF was cleaned, but sometimes it can be confusing, since there's 2 areas of wires, but you cleaned the one set of two thin wires right? The one you have to look down into, vs the wire that's covered in whatever insulation and easily seen once you pull out the unit?

aerobat66

Now I have a P0305 code. Misfire in cylinder 5. It idles rough and is barely driveable.

I am waiting on new coils to arrive and will have an update next week. At 185k miles, it's not a bad idea to replace them anyway. I think it is either the coil, or I got a bum rebuilt OEM injector.

I just replaced the intake plenum gaskets, as I strongly suspected the OEM ones that were delaminating. That wasn't the problem.

It is not burning coolant, and I did the test for exhaust gas in the coolant a while back. I really don't think it is the head gasket.

I did clean both areas in the MAF. Original fuel filter was replaced not too long ago.

75w90mantraN

Do you recall the previous cylinder that you had an injector issue with?

Already ordered coil packs...185k is kinda young I think, but yeah, I would check that. Where did you order yours from?
You can test the resistance on the suspected coil pack in the meantime. Or switch it with another cylinder and see if the code sets in a diff one...
Troubleshooting is a pita. Seems like you're narrowing it down. Keep us posted.

aerobat66

I just installed the Denso 673-1201 coils I got from RockAuto. Fired it up and it purred like a kitten. I was grinning, until I was going down the road on a test drive and it started missing again.

After it cools down, I will switch out rebuilt OEM injector #5 for the old one. If the problem goes away, then Bingo. Then I will return that faulty rebuilt one to FiveOmotorsports and get another. If swapping injectors doesn't work, then the problem becomes really mysterious.

Then previous injector was #4.

A smart person learns from his mistakes. A real smart person learns from other people's mistakes.

I don't feel too smart right now, after spending money that didn't have to be spent just yet.

75w90mantraN

I feel your pain. Dealing with p0303 and p0300 codes that came under towing a load on the uphill grades but went away. But the symptoms are still there.

I thought maybe my injectors are going bad...but I checked resistance on #3 and a good one and mine are ok. I disconnected mine while the engine was running and both gave me indications they weren't shot yet...

So I checked coil packs and forgot about the corroded one for cyl #1 and 4. Pic shows where. Resistance was flat.

Another coil pack was on its way too, but I managed to salvage it by switching the coil boot off the bad one onto it and the resistance stayed solid with specs. This pack was getting weak. That p0300 can mean any cyl.

I said on another post about having new plugs and wires. Well, first time's a charm with those iridiums. The gimmick about them lasting for the next 100k isn't working for me. Yeah if EVERYTHING else is working properly, but lets get real, parts upkeep is usually when we get symptoms or codes and as these Toys get old, living up to that claim I can't do. Oh well. Lesson learned.
Check out my 'still new' plugs from cyl 3 and 6. Guess which code that one was responsible for? I put in those plugs less than 4-5 yrs ago. Dont drive much annually. Hmmm.
May need to recheck stuff you initially thought was good.

aerobat66

I will study the plugs and wires tomorrow. But after I take my seemingly dying 12.5 year old German Shepherd to the vet in the morning (in my T4R which runs real bad), probably to have her put down. When it rains, it pours, as they say.

75w90mantraN

Not feeling smart...I feel that way all the time. So don't sweat it. Check the injectors by disconnecting them while the engine is running and if the idle gets worse, that means they're doing their job. Of course that can be hard if it's on the other cyl right underneath the junk. So test #1. If that checks out fine, more than likely all other 5 are good since they're the same brand.Then you don't have to redo all that hard work and it be safe to knock those off your to-do list in the future.

I wouldn't be surprised my issues still continue (but I hope they don't). But I know it will at least run better. These guys need a lot of tlc.

Let us know how it works out.

Sorry about your shepherd.

75w90mantraN

At the very least, if code p0305 and no others, I would check wires, plugs, coils on cyl 2 and 5. Ignition system is dual, since both cyl rely on one coil pack. Any other misfire codes or issues continue, I'd check the rest.

aerobat66

That's my plan. Just installed (3) new Denso coil packs, so I can most likely rule out that. Checking plugs and wires (recently replaced, with NGK) are next, then if nothing there, I will swap an old injector for the currently purchased rebuilt injector in #5. If still no improvement, then this problem is in the twilight zone.

One of my daughters is 3/4+ way through veterinary school. I recently told her that junk like this is precisely what doctors do, yet on living organisms, instead of machines. It really is. Sometimes, all you have is a hunch and/or your best guess. After all, isn't that why they call it "practicing medicine" (with emphasis on the word "practice").

I find it a very odd coincidence thought, that **immediately** after replacing 6 injectors, my CEL comes on, and the previous "kinda rough idle when hot" went to real rough idle, and very rough running, just going down a flat road.

"Doctoring". Seriously. (I just wish my daughter wouldn't get insulted when I say I am doing essentially exactly the same thing she will be doing in another year)

75w90mantraN

There's a saying, 'sometimes it gets worse before it gets better.' Doctors mention that all the time, like with treating colds. I agree there are definitely parallels between the two 'practices'

aerobat66

Spark plugs #5 and #2 (NGK BKR5EKB) looks ok. Not new looking, but not bad. They both look about the same as plug #3. NGK plug wire #2 looks ok.

Besides a faulty newly rebuild OEM injector, what might cause a misfire in only cylinder 5?

The only remaining thing I can think of doing is swapping injector #5 with one of the old ones and see if the problem goes away. Or swap 2 of the newly rebuilt ones and see if the misfire moves to another cylinder. Either way, I have to remove the intake plenum yet again, and twice, to finally fix the problem if it is an injector.

Any other ideas?

75w90mantraN

I take it the wires have no corrosion, have no carbon tracks or fouling for the visual check. Depending on how close you are to their next change interval is your call.

If the injector is suspect, your method sounds reasonable, so let us know what you get. Guessing the old injector comes off a good cylinder.

If no other codes, then perhaps a misfire caused by something else...read about crank pulleys being a possible suspect, if recent timing belt work and chance of improperly torqued pulley bolt or crank/cam shaft sensors going bad or just dirty.

Doubt it be fuel pressure or fuel pump, as I'd think you'd have other codes, but you never know. That 5th cylinder may have thrown in the towel, but the others could be giving you symptoms without a code yet... So fuel pressure testing maybe another avenue.

You could do a compression test on the bad cylinder and compare with the rest, but if you're not burning oil, I kind of doubt that.

I've read a lot of injectors being the culprits, but it helps to keep the 'innocent until proven guilty' concept in mind.

And the saga continues....

aerobat66

Purrrrrrr. Vroom vroom. Ahhhhhhhhhhhhhhhh

Apparently, injector #5 was bad. I swapped the original #2 injector for it, took it for a long test drive, and she runs great. Now I suppose I will find out if FiveOmotorsport stands behind their product and replaces it.

This sure was a major learning experience for me. I'm not done yet, until I replace that injector with a rebuilt one, but at least I can drive it until then. Or maybe I should knock on wood.