Slight engine missing when the head lights are on!

[alia176]

This is a new one for this car. While I'm sitting at a red light, if I turn on the side marker lamps or headlamps,, the engine starts to miss. Not bad enough to stall the engine by any means, but you can feel and hear the hiccups. Turn the lights off, everything is silky smooth.

Obviously, a possible short somewhere but has anyone experience this before? If I recall correctly, this is similar to the crankshaft position sensor doing something similar. The shielding on this wire is exposed so perhaps an EMI is being created? Just a shot in the dark!

[Mr. Claret]

Don't overlook the possibility that you battery or your alternator is weak. Free 'load' tests can be attained at most auto parts store (i.e. Autozone, Advance Auto, etc.)

You may also want to double check that the TPS is properly adjusted. I know when I turn my lights on, typically when cold, RPMs fluctuate quite a bit sometimes.

Just my $.02

[Crazy_pilot]

A dying alternator will produce all sorts of weird symptoms in our cars. Mine was misfiring, making thumping noises from the stereo, and could barely drive forward. Definitely take a look and see what sort of voltage it's outputting under load.

[icingdeath88]

Check your grounds also. Battery -> chassis and chassis-> engine. The chassis ground is on the horn bracket in front of the battery. The engine ground is on the engine block somewhere near the starter.

[alia176]

Originally Posted by Crazy_pilot

A dying alternator will produce all sorts of weird symptoms in our cars. Mine was misfiring, making thumping noises from the stereo, and could barely drive forward. Definitely take a look and see what sort of voltage it's outputting under load.

Had the charging system checked out and all is good.

The intermittent issue has gone worse by the end of the day. Now, she misses while idling with or w/o an electrical load turned on. I even felt couple of hicckups while accelerating as well.

Looks like the miss is being caused by spark escaping out of the spark plug coil, cyl #1, #2 or #3 is the culprit. I can hear a spark jump and see the engine miss. I bet one of my spark plug coil housing is probably cracked and causing the spark to ground out.

Will check the ground today, thanks for the suggestion.

[oab_au]

Originally Posted by alia176

Had the charging system checked out and all is good.

The intermittent issue has gone worse by the end of the day. Now, she misses while idling with or w/o an electrical load turned on. I even felt couple of hicckups while accelerating as well.

Looks like the miss is being caused by spark escaping out of the spark plug coil, cyl #1, #2 or #3 is the culprit. I can hear a spark jump and see the engine miss. I bet one of my spark plug coil housing is probably cracked and causing the spark to ground out.

Will check the ground today, thanks for the suggestion.

Yes thate sounds like the cause, the coil may not be cracked, just have a burnt track down the side, that can be scrached out and sealed with silicon spray.

Harvey.

[alia176]

Well, it turned out that #2 ignition coil (middle, passenger side U.S.) was the culprit. Swapped it out with a brand new unit and all is well.

I'll replace all plug coils eventually as they have around 150k miles on them.