Misfire with A/C On

[Fishinguy40]

2000 Malibu, 3.1 liter. Got home last night and the wife informed me that the last couple days while it was really hot and she had the air conditioner on that the car hesitated/jerked as she was driving and the check engine light began to flash. She turned the A/C off and car drove fine. This happened twice. Both times turning the A/C off corrected the situation, according to her.

The hesitation/jerking along with the check engine light flashing tells me that the car was experieincing a misfire. I haven't had a chance to get up to an auto store and read the codes but figure that I might only get a random misfire, which won't tell me much. Also figure if it was bad enough to cause the car to hesitate/jerk that it was probably more than one cylinder.

Any ideas why it would misfire only when she is running the A/C?

[fishhuntwork]

It sounds like it could be possibly bad spark plug wires due to the load on the motor with the a/c on.

[fishinarc]

second the spark plug wires

[Jeremy airjer W]

It should give a specific cylinder(s) if the light was flashing. Just to thruohg out some other ideas If it is a specific cylinder and it is fine after the car cools down and only acts up when its hot i'm going to say fuel injector for whatever cylinder is affected. The good thing is that if it is one cylinder and its acting up you can usually hear them not working if you use a long screw driver as a stethascope. If it isn't working a light tap with the screw driver will usually get it working again and/or confirm the bad injector.

Otherwise I am on board with the tune-up suggestions.

[jeffreyd]

could be the electric cooling fan not coming on or barely coming on. carefully reach in with engine off and key out of ingition and move the fan. use gloves as the blades are sharp. any side to side movement or if you can shake it could be the cause. there should be a plug ontop of the shroud that you can take apart, and the fan should lock into the on postion. you can then hear if it is dragging without possibly cutting yourself too. good luck.

[Jeremy airjer W]

could be the electric cooling fan not coming on or barely coming on. carefully reach in with engine off and key out of ingition and move the fan. use gloves as the blades are sharp. any side to side movement or if you can shake it could be the cause. there should be a plug ontop of the shroud that you can take apart, and the fan should lock into the on postion. you can then hear if it is dragging without possibly cutting yourself too. good luck.

Not sure what that has to do with a missfire? Maybe if the car was overheating. You might be thinking of another problem on a completely different vehicle?