ok CEL came on, i got a diagnostic tool and it gave me back "random/multiple cylinder misfire detected"

car is 99 maxima, im thinking its coils, but dont have the tool the check them. any other ideas of what it could be?

things i recently did:
-spark plugs a few weeks ago
-fuel filter
-MAF cleaning
-pcv valve


i know only the plugs really have much to do with the code, but just a heads up incase one thing could have lead to another? i dunno. HELP ME OUT! =)

 

anyone??????

 

Some things to try:

- unplug each coil one at a time with the engine running. Is there one that does not cause a drop in idle speed?
- if so, listen to that injector compared to the others to see if it's working
- Check coil(s); shut off engine and pull each coil one at a time and connect to a known good spark plug. Crank the engine and watch for a spark.

Other potential causes:
- low fuel pressure
- low compression in one or more cylinders.

 

Definitely Coils! There's a trick to it though. My 99 SE had the exact same issue. I was not going to replace all of the coils at once. I reset the CEL, and waited for it to pop up again. The second time that the CEL came on, the code gave me the cylinder that was causing the problem. Replaced it, and I cruising again. However...it started again... This time, more than 1 coil was misfiring. I decided to end the dilema and replace the rest of them. I also replaced my plugs with NGK V-Powers and I haven't had a problem since. MY Max runs great now! I am assuming that you are well over 60K miles....that's when the coilis typically start to go bad.

just my $.02...

 

yep about 120K...when i take the coils out to test them can i just disconnect the plug(not spark plug, the clip plug thing) that goes into them or should i pull the whole coil all the way out? and when im testing, if the RPMs do not drop then you know that coil is bad right?

oh yea and another question....when i start my car the RPMs go to about 1500 then it drops to about 500RPMs like its going to die, then it sort of catches itself and revs back up to about 1300RPMs....does this sound like a coil thing?

 

eh?? anyone? lol.....

 

99's are notorious for bad coils and misfire codes. Your better off biting the bullet and just getting a complete new set.

 

yea i hear that quite a bit...but i just tested them by unpluging them, and all 6 seemed to drop RPMs...which from what i understand means that they are good.