Ebin

I've got a real head scratcher on my hands here. The engine misses on acceleration and while cruising in 3rd and 4th gears between 30-50mph. Miss is definitely in engine and not in drive-train. Also, gas mileage doesn't seem to be affected and I'm using about 1Qt oil every 10 days. Here are the things I've already tried:

1. Changed fuel filter
2. Set timing
3. Changed spark plugs and wires (NGK)
4. Changed distributor cap and rotor
5. Checked for vacuum leak (none found)
6. Changed vacuum line check valve
7. Changed oxygen sensor
8. Cleaned throttle body
9. Changed PCV valve
10. Cleaned top-end of engine with Sea Foam (many cans)
11. Used multiple cans of fuel injector cleaner
12. Used RESTORE in crankcase

One possible cause of problem I can think of is, I had 1 spark plug that wasn't seating completely because of marred threads (this problem has been fixed) thus allowing possible compression issues. Plugs are black with some clumps of white carbon on electrodes. No oil is present on plugs, plugs are dry. Another clue of a possible compression problem is when I release throttle quickly the driveshaft seems to hit rear xfer case pretty hard, although this problem has been greatly reduced with the Sea Foam run thru to clean top-end of engine.

TNRabbit

So you have an "under load" miss. That's unusual because misses usually show up in a "no load" condition.

If you're using that much oil, I hope your driving cross-country! How many miles to use a quart?

Have you checked engine codes? (I'd do this first)

Have you done a compression check? (do this second if you get no codes)

Is the distributor in good condition?

keithguts

Does the miss go away at over 50 mph?

ChickenLover

Definitely do a compression test. Is your engine temp effected at all? 1qt every 10 days is insane. I suspect a blown head gasket. Have you checked for oil in the radiator?

toyotaoffroad91

+1 blown head gasket or #6 intake valve burnt up do a compression test

SCdudeBro

Hopefully we will see an update on this thread. I did a search for a very similiar problem. I'm going to give my truck a tune up and see what happens. Keep us posted.

MonsterMaxx

suffering with the same problem here.

Cyl#4 is a deader (30psi of compression.)
Just spoke with Toyota and they claim that they have NEVER had one with oil & a headgasket failure, always coolant, not oil.

Furthermore, the whole headgasket recall (Toyota paying for it) is OVER.

So...is there any point of tearing this down or should I just get on with putting a Chevy in there and be done with this 3VZE crap?

Bumpin' Yota

LS1 gets my vote!

Ebin

Yes, 1 Qt every 300 miles is insane (but, engine doesn't smoke). Seems TNRabbit and I are on the same path. My last two solutions to a cure would be a burnt valve or a bad distributor. No engine codes what so ever. Compression check is next route. And yes Keithguts the miss does go away at 50-55 MPH. No oil in Radiator fluid. Radiator clear and clean. Lost here too MonsterMaxx.

hamish_18

okay I am having the same problem. under light load. If I full throttle it the mis fire almost goes away and the power that should be there. I have done all the regular maintenance that you should do. and I have done most of the other things. I have done a comp test. all the cylinders checked out and were all within 1 psi of each other. and was like spot on with what they were suppose to have I don't burn oil really that badly, never need water. ever, everything seems good. I just don't get it. and now yesterday I checked my computer to see if it had any codes and then I reset the ecu and now it is misfiring almost unsafely. I am about take a shotgun to it. I have searched and searched on mulitple sites, and a lot of people are having what seems to be about the same thing, but nobody ever has a good solution. or if they do, it doesn't help when I try the solution. I don't want to take it to the dealer because they are gonna just check the computer and say nothing is wrong with it. and then charge me 200 bucks for labor or something. has anybody on this forum had these problems and figured out what was wrong?? thx in advance,

Chris

TNRabbit

Hamish: check for a bad distributor.

Bumpin' Yota

exactly my thoughts as well, check your engine timing as well...

MonsterMaxx

I'm not lost anymore, I used a scope last night and looked down the hole. It scuffed a piston and scored the wall in #4 - pretty badly too.

Darn thing was running pretty good too, don't they always just before they die?


This motor has always had oil pressre problems (low) from the day I got it back from DOA.

I'd like to thank Tim 'the dickhead' Jenkins from DOA racing for building me one unbelieveable piece of crap. $10,000 for 30,000 miles. WTF?

hamish_18

we tried that. we even swapped out the distributor in his toy and put it in mine, and then re timed it. it didn't fix anything. so we just left it. but I did put a new cap and rotor in there. still didn't fix it. it was wierd too. when we were setting the time on it, you could hear the mis in the motor. we hooked the timing light up to the ignition wire, and it would light up even when it missed. hmmm we never tried just hooking the timing light to each wire to see which piston was actually missing tho. damn. just thought of that.

Bumpin' Yota

hmm sounds like cyl #1 isnt firing! you may have a bad sparkplug wire..

hamish_18

what makes you think cyl 1 isn't firing?? oh ya brand new plug wires too. okay today tho I checked the resistance on everything I could get my hands too. and the only thing that wasn't up to spec was the primary ignition coil. in the book it says .35-.50 or something like that, and mine was sitting at .7-.8. So if the coil was going bad, would it show a higher resistance like that? could I just not be getting enough juice to my spark plugs and so its hit or mis? I really hope this could be it because I want my truck back the way it was. Also I have never heard of ign. coils going bad? hmmm. anyways. thx for the help so far.
peace

Bumpin' Yota

well if you had the timing light hooked up correctly and it works and shows no flashes when you pull the trigger, then there's no spark going through the wire the timing light is using to sense.

iirc - the timing light had a + and - that you hook up to the battery then a sensor that goes around plugwire #1, you then point it at the crank and pull the trigger. It should flash every time #1 cyl fires. If nothing happens when you do all of that, then either the timing light is bad or there is minimal to no spark going to #1.

If none of the wires are making it flash it may indeed be the coil...though ive never heard of one going bad

hamish_18

nonono you mis understood me. ya we had it right, cyl #1 was firing fine. light was coming on and everything. but after we timed it, there was still a mis. so he tried just putting the signal wire or whatever it is around the main wire, to see if the light came on when it misfired, and it did. thats all I was saying about that. okay hope that makes more sense to ya

TNRabbit

hamish: Have you checked the TPS to ensure it is properly adjusted? They can be a real pain in the @$$.

hamish_18

well I think he did, but yesterday I hooked my multimeter up to everything I could get my hands on. I thought I had posted that in my above post, I guess I was tired. oh wait I did. so guys, would .7-.8 ohms be to much resistance? when it suppose to be .35-.50 ohms? and I couldn't get to the tps to test that. how the #@$ are you suppose to test that thing. I don't want to take it off. and I really don't want to take my throttle body off. I will if I have to though. I think I actually have it narrowed down the the primary coil, and maybe the tps now. keep the hints comin guys your doin great!!!