4runner running rough at accerlation and engine light on...

[FLETCH504]

I have a 97 4runner, the engine light has been on and its been running rough (missing) upon acceration... the code is pulling up cylinder 3, compression checks fine, i've replaced the plugs, cables and coils. any ideas, of other things I should check?

Thanks,
Rob

 

[Duane]

3.4 I assume or 2.7L ? just to confirm.
Runs smooth at idle but hesitates upon acceleration?
Can you reset/clear the engine code and does it keep coming up with cyl#3? or is that what came in once?

If spark is getting there and it is advancing/retarding properly then perhaps fuel.... injector.... fuel filter

What did the plug look like that came out of #3 hole? and was this the same as the other plugs?

 

[Jeremy9A]

If you are sure you have good spark and compression, you may have a bad injector. They can ohm out good, but be mechanically stuck sometimes.

If you can see the injector, try to LIGHTLY tap on it with the engine running. If it is a mechanically stuck injector, it may smooth out and run fine. Very common on GM's, but can happen to any.

good luck

 

[raydouble]

x2 on the possibility of the injector.

 

[brian2sun]

x3 on the injector, that's the next likely cause since you've already ruled out the plugs/coils. At least #3 injector is easy to get to (the other side of the engine requires taking the intake plenum off). After injectors, the next thing I would suspect is a sticky valve, but it's not nearly as common on the 3.4s.