We haven't tried a new fuel filter. YET. Trying to work our way up from least $$ to whatever we need to do.Can tell you that the service engine light was blinking beforenew plugs went in , now, it's steady. Husband says it still seems like it's running on 7 cylinders. Going to take it back apart and switch a "wire" (from the coil pack to plug) to see if a problem lies there. when he steps on the gas pedal, it goes up to about 4000rpms and then drops down....? I'll let you know how our white pearl beast makes out.
Kim

 

Was there an engine wash before this problem started? That can kill a bank of coils.

 

No, no engine wash. It just happend out of the blue. Fine one day, the next it wasn't bazerk at McDonalds. We're puttingon a new fuel filter now. I realy hate spending $$ if it's not the coil pack. Like I said earlier, it seems to be running on less than 8 plugs. Hubby took it apart to see what the new plugs looked like and the 2 of the four seemed like they were brand new, while the other 2 looked carboned up. ???? Put the cleaner in the tank. What's next?
thanks for ALL your help and suggestions!!
Kim

 

Reporting in to say that she's still running rough. Put a new fuel filter on and didn't do any good. What can be the reason for at the first attemp to change the plugs, 7 of 8 looked good. 1 was black and carboned up. Put new in and then 4 of 8 looked good. 2 didn't look as if they were giving any spark and the last 2 were all black and carboned up. I pulled the codes again and it still gives me the general code of P0300, "engine misfire detected". ?????

Kim

 

I suggest checking the spark plug boots for cracking and proper connectivity, replace if needed. Make sure coil assembly is reinstalled properly. If all of this fails then you need to isolate which cylinder(s) are misfiring and this will mean going to a shop.

 

Ok,
this is what we ended up doing, it's a personal issue now....the plug that showed no fire, we switched a fuel injector over to that plug and that is now fireing. It looks like a faulty fuel injector.
It's now on order and I'll check in tomorrow morning with the results.
Kim

 

O-Rings are cheap .. a '91 car will have rubber parts over 15 years old, with rubber parts that are seeing the end of their life cycles.

no wires? the injectors dont have wires?

steel wool .. a NO-NO on electrical parts, specially plastic or aluminum .. the use of steel wool on any surface except S.S. will leave microscopic steel particles embedded in the material which will later promote rust or an electrical path. next time use a non-metallic fiber scouring pad & Bar Keepers Friend. in fact, you may want to re-clean with it as it will remove off the steel particles left behind.

 

All good advice Stomp.

 

Great! After reading this to my husband he says, "that's true"....... (about the steel wool factor) Bar Keeper's Friend is a good product.
anyway, going to let the car cool down and out the new injector on. Got new o-rings. car is 7 years old, was running fabulous till this occurance.

 

This is the exact same problem I ran into earlier this week, I have not had a chance to troublshoot the problem with work and all but did the fuel injector work out for you?