Engine keeps missing

[TRDyota]

I've got a 97 4runner with the 3.4L v6, 4x4, and 5 spd tranny. When in gear and off the clutch, the engine is shuddering at low rpm (under ~2200 rpm). The shuddering is greater in the 4th and 5th gears. The higher the engine load at low rpm, the greater the shuddering.

At first, I thought it was the clutch slipping, but its not the clutch (which has been confirmed by a mechanic).

So what would cause the engine to miss only while under load? Everything is fine at higher rpm (even in 4th and 5th gear), or with no load at all.

[TRoss]

Sounds like ignition to me...
Plug wire would be my first guess.
Spark plug my second guess.
Individual ignition module thingy third guess.

Good luck with it!

[TheAussie1]

Sounds like a miss, is there any noises coming from it?




lol, I was waiting for someone to say something about the thread topic being, engine keeps missing, and say something

[VTCpres]

are you possitive its coming from the engine? or is the vibration coming from the front of the rig? What exactly is the sound? shuddering isn't really a sound, more of a vib. Im with the rest on the miss, but it could be numerous things.

[LSUTacoma]

I recently had the same issue with my '03 Tacoma with the 3.4. It only shuddered at idle when in drive. My scangauge picked up a code saying Cyl 3 had issues. I started with plug wires and plugs, figured it was time for them anyway. That was 2 months ago and the missing still hasn't returned, runs great!

[TacoCrazy]

I've got a 97 4runner with the 3.4L v6, 4x4, and 5 spd tranny. When in gear and off the clutch, the engine is shuddering at low rpm (under ~2200 rpm). The shuddering is greater in the 4th and 5th gears. The higher the engine load at low rpm, the greater the shuddering.

At first, I thought it was the clutch slipping, but its not the clutch (which has been confirmed by a mechanic).

So what would cause the engine to miss only while under load? Everything is fine at higher rpm (even in 4th and 5th gear), or with no load at all.

Miss under a load would indicate an ignition issue..Ie, plugs, wires, coils..
When under a load you are asking the ignition to do more work and if there is an issue there it will generally rear it's head then. If you haven't changed plugs in the last 30k miles then get a factory set of plugs and start there, but I'd bet you have a coil issue, very common on the 3.4. :2cents:

[TRDyota]

Will pull some plugs and check it out. Should the check engine light come on when the engine misses? There was no history of cylinder problems detected by the scanner.

[TacoCrazy]

Will pull some plugs and check it out. Should the check engine light come on when the engine misses? There was no history of cylinder problems detected by the scanner.

Not necessarily, I had one for about 4 months and never got a CEL.

[TRDyota]

Is there any way to isolate the coil to make sure thats what the problem is? I wanted to avoid just replacing stuff until the engine works again, but it sounds like I may not have a choice.

[TRDyota]

I forgot to add that the mechanic's scanner came back with the following code:

DTC P0440: Evapoative Emission Control System Malfunction.

...probably unrelated? In the 1 year that I have had this vehicle, I've never gotten a CEL.

[footheter]

throttle position sensor? im pretty sure thats whats wrong with my 22re:confused: same symptoms.

[megayota]

It sounds like a TPS

[mudinman]

the code is unrelated, evap codes and runability are very rarely connected. Check your spark plugs for carbon tracking, a little black line going up the plug, if there is carbon tracking then replace the plugs and whatever is firing the plug, either the coil or the wire. The reason is there will be a matching line inside the wire or coil and eventually the spark will jump out and follow the line again. If that is not the problem then you may have a bad injector on the misfiring cyl.

[footheter]

just replaced my tps still the same. :mad::confused: wtf!!! i wanna know what is wrong with my truck i did everything on this thread. what now??:mad::mad::mad::mad::mad::mad::mad:

[TRDyota]

I never did post my resolution:

Out of frustration, I started pulling plugs. There's only 2 plugs on the 5vz-fe that are easily accessible. After removing the wire on the second plug (middle, drivder-side cylinder), I noticed that the plug socket would not fit over the plug. I got a flashlight and shined it down into the cylinder and saw that the wire had actualled burned up onto the spark plug and ripped out of the wiring "boot". I was able to retreive the wire with some needle-nose, then was able to fit the socket over the plug and pull the plug. Replaced wire and plug, and everything is honkey dorey now. New plug was $3, new set of wires was $40-something.

I would suggest inspecting plugs and wires if you are getting shuddering from the engine.

You can test if its the clutch by stopping the vehicle, putting your foot on the brake, and easing the clutch out. If the engine rpm gets pulled down, then its not the clutch. If the clutch comes all the way out and the engine does not die, then you have clutch issues.

Hope that helps.
-Brandon

[RU55ELL]

I still need to check my TPS. I replaced the plugs, wires, cap and rotor and fuel filter. Still have a miss at idle.