OK here it is, when i start the car up (cold) it idles normal like 1300-1500 but the engine JUMPS UP AND DOWN, as it gets warmer and the idle drops it slows down the shaking but doesnt stop it, now that its fully warm the idle usually surged from 900 -1300 or so because the 02 is not wired yet, but now after headgasket replacement, the car surges down to about 400 (almost shuttin off) but it wont die, it will idle like that forever surging uppppp and downnnnn?????????????

any help please!!!!

 

the o2 sensor has nothing to do with it
take your IACV off and clean the little screen. (should be on the bottom of the intake manifold)

 

either eacv or fast idel valve(cold start valve) the eacv is trying to keep the idel at normal speeds while the car is cold but if the cold start valve doent open the eacv will want to compensate for the vacume loss.pwn3d