Hello everybody;

I have an intermittent misfire on a few cylinders, but not very often and quite random (I've seen 1,2,3,4 and I think 8 of various occasions). the car is idling rough and occasionally stalls. I don't think its the fuel pump or injectors (both serviced/swapped to no effect) and nice new sparks did not solve the problem.

Could it be faulty coils? Any way to test them (other than swapping around)?

Note: the kitty is due for timing belt swap/upgrade (next month methinks) could this be the cause of misfires and rough idles?

Any thoughts much appreciated.

 

My remote, very remote, analysis based on your classic symptoms of misfires, rough idle and stalls is that you have jumped a tooth on your exhaust cam sprocket on the right side.

Your car doesn't have a timing belt but does potentially have timing chain tensioners that have a terrible history of failing and destroying engines. Jump one tooth you get misfires and rough idle, jump two teeth you bend one or more valves and replace the engine.

I say potentially becaues '02s were supposed to have the upgraded metal tensioners but not all did. Mine did not.

I would not start the car again, not even once, not even to take it for repair, before removing the right valve cover for a look.

After that is verified/resolved the standard method of testing coils is to swap them around.

 

I agree that you should take the precaution Test Point has suggested.

If you do determine that the tensioners are OK, then reset the codes once you have a warm engine. Then restart the engine and check immediately to see which cylinder misfire(s) occurs first. The first one or two to register are usually the culprit in a multiple misfire situation.