My wife's 2001 Tahoe with the 5.3L has a very bad surge at idle. You can see the lights dimming in and out, the A/C doesn't work until you get going, and sometimes it cuts off when you hit a bump. I've changed the fuel filter and spark plugs already. I'm waiting to see if anyone has an idea before I spend the $600 on coils and the time to drop the tank and check the pickup.

Dan

A surge at idle can be caused by a dirty Throttle Body, Dirty MAF, a vacuum leak, faulty PCV, fuel pressure regulator, etc etc etc.

If one of the coils was bad, the check engine light would come on.

Before you drop the tank, test the fuel pressure first. If the pressure is good, there is nothing wrong with the pump or pickup.

It would be a good idea to clean the Throttle Body and MAF, check for leaks and replace the PCV.

//2000CAYukon