Bad coil pack -- HELP!!!
 

Intermittent stumble at idle, and it misses when accelerating in overdrive.

Should there be a Check Engine Light? Is there a way to tell which coil pack it is?

Thanks!

Re: Bad coil pack -- HELP!!!
 

what year is your car? if you have OBDII, then you might get a misfire code with a scanner. otherwise, search for "diagnostic connector" on here and find the procedure for the earlier models.

when mine was misfiring, it sometimes didn't throw a CE light - only if i was going up a hill and it did it for a certain amount of time.

It's a '93... 135k miles.
How can I determine which cylinder it is?

OBDII will tell you which cylinder. i don't know about the earlier codes - have you searched for them, and the procedure for retrieving them? i imagine it would have a separate code for each cylinder.

Pre- OBD2 cars won't set a code for a skip. If its definitlly a dead skip you can try unpluging one coil pack at a time to find the bad cylinder. It will be the one that doesn't change the way the engine runs.

Just a point. If Henry is going to run the car under load on the road, to find the bad cylinder, it would be safer to pull the injector plugs instead of the coil plugs, so it does not run unburnt fuel into the cats. Should still be able to find the cylinder the same way.

Harvey.;)

Easier, too. It's hard to reach those coil connections.

However, it's an intermittent problem. In the repair world there's nothing I hate more...

could be other things
 

usually a bad coil pack isnt bad just at idle....
a stumble could be old spark plugs, bad TP sensor,
dirty or bad Egr valve, mass air flow sensor on the
verge of going bad, or even the crank trigger sensor......
Pick one or pick them all ....good luck