Well, this is a 94 ls. Every once and a while I will start the engine and the revs will just fall until the car stalls (clutch is in), then it wont start for a few times or until i give it some gas, this is a fairly rare occurence but it is still bugging me. The idle moves a slight amount lower when the AC is on. What is the deal??

 

I'm not sure what is wrong with the car stalling.

But when your A/C is on, the compressor is using power from the engine and the tach will drop a little bit.

Notice when you are sitting in you car and have power steering. Turn the wheel to engage the P/S. Look at the tach, it'll drop a bit b/c the p/s pump is taking power away from the motor.