Running rough/misfiring?

FLORES22

MEMBER
1993 TOYOTA 4RUNNER
6 CYL
4WD
AUTOMATIC
18,100 MILES

I have a 1993 4-runner that is running rough/missing? I have replaced the plugs and wires (intially found a wire sparking, which I tought was the problem), the engine still running rough. Should I replace the cap/rotor as well? Also prior to running rough, truck sounded as if muffler was in need of replacement (basically due to the sound). I have looked over the muffler and it all appears in decent shape, could my problem be in the catalityc convertor?

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

A rough running engine could be caused by any of the things that you mentioned including a couple other items.

So the unfortunate thing is we need to start running through all these items until we start to find something that is causing this.

I would suggest starting with the ignition system if you have not changed that in a while.

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Once we know the ignition system is ok we need to move onto these other items. However, at that point we need to know if it is actually misfiring or just running rough.

Do you have any codes? Here is a guide that will help with pulling codes:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If you have misfires then this guide covers the common causes of misfires which is what we need to do to figure this out:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

However, if there are no codes then we need to check for a vacuum leak which is what I suspect the issue is.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please run through all this material and even if something doesn't fix it let us know, because that is good info to point to what the issue could be.

Thanks