ok i thought it was my TPS maybe i havent adjusted it correctly but here goes, once i start my car from a cold start the idle is good well its good for me cuz if the engine is warm the idle is a bitch, at a cold start it stays in between 1000 and 2000 usually 1100 but off and on if you know what i mean, but once i drive it hard, like just shifting to second and third at around 4-5k idle just drops to 800 and just tries to stay alive but it doesnt last for more than 2-3 tries of trying to stay idle, everytime it almost dies out i hear a "pssh" sound like a blow off valve sound type, i think that its my TPS (i bought a new one and it still does it) but then i thought about it more, maybe i have a vacuum leak?? blah i just wanna fix this idle bullshit cuz its kinda hard holding idle everytime i ******* drive. oh and my car is a 86

 

The S4's TPS just tells the ECU that the engine is supposed to be idling.

The BAC is primarily responsible for idle speed.
Start by cleaning & checking the BAC & it’s connector.

Of course a vac leak will screw up all idle settings & controls.