i'm confused with my problem. on cold start ups my idle is at like 1500+ rpm and it sometimes loops from 1500-2000 which continuously goes up and down and this only happens in park or neutral. when i shift into gear my idle is at 1000-1100 and the engine seems to be pulling a lot but the looping never occurs which is odd. after driving for a long time and when the car is warm the idle starts to drop slowly and slow until eventually it hits 0 rpm and stalls. after the 1st stall the car doesn't start up unless i give it a gas and it stalls if i let my feet of the pedal. im also having problems when i drive on the freeway. when i let go off the pedal the car jerks suddenly like it slows down or down shifts oddly and it's real dangerous. what type of problem could this be?? ecu related, iacv, fuel, tps, throttle cable?? any help??

i bought an iacv from aliga them but installing the iacv they sent me was even worse. the car didn't start up at all unless i gave it a gas and keep my foot on the pedal. could it possibly be the ecu???

 

I think you just have an vacuum leak somewhere. Now time to find it.