94 Rough Idle when lights or AC are on - Toyota Nation Forum : Toyota Car and Truck Forums

dantheprintman · 06-24-2011, 11:37 PM

Hi all my name is Dan, and I am new to this forum!

For about 2 weeks now my car (A 94 Corolla 1.6lt 5speed with 145k miles) has been having a very rough idle. The strangest thing about the idle, is that it becomes worse when my headlights, or AC are turned on. Any suggestions, I am not sure what other information I should be giving. So please ask away. Thanks in advance!

NWMO 95 Prizm Lsi · 06-25-2011, 11:09 PM

Hello Dan,

Not a lot of info, but from what you have shared, I would want to check the alternator. It sounds like the alternator does OK with minimal load, but when you start using the high amp items, it likely pulls the voltage down on your ignition system, causing a puny spark and rough idle.

Chris

speedy25 · 06-26-2011, 12:13 PM

99% of idle problems are with the idle control valve. Usually it just needs to be cleaned.

-SP