I noticed that my idle surges when I am stopped at redlights and other times when I'm the car is stopped in Park, Neutral, or Drive. It goes from the normal 600rpm's to 500 for a second and then back. Feels like a very slight stall. I cleaned the throttle body, MAF is ok, tune up, new fuel and air filter. I thought doing these things might cure the problem, but it's still there. It's not major but annoying as hell. Any ideas what it could be?

 

I experience the same thing. Sometime it happen, sometimes it doesn't. But when it does happen, I am stopped and my foot is on the brake. When I let off the brake it stops. I was told this is a vacuum problem caused by a leak in the booster which affects the vacuum controls on the engine

 

How do I check the vacuum leak?

 

Whats the condition of your battery,if the revs drop whet you put you brakes on ,the power needed(not that is bugger all)to make the brake lights go could be to much for an old battery.therefore its sucking load of the alternator which inturn puts a little load on the engine ,just enough to notice .
Just another option to look at anyway.

 

That might be true, but my battery is only a year old. Could it be that I have two amplifiers hooked up to the battery for my sound system? Could that affect the rpms and how would I test the theory of the battery and altenator?

 

yeah big sound systems can make life tough on stock electrics,you made need a better battery or alternator,try disconecting the stereo for a day & see what happens.

 

I might try that to see if it helps, but it's going to be hard not to listen to music for a day.

 

Might want to check out this article,

SURGING IDLE ARTICLE