My 1986 tpi 5.0 305 trans am dies when i try to adjust the idle

it starts and runs around 300-400 like its gona stall then shoots to 2300 and idles down to 1200 then 1100 then 1000 steady until it warms up then goes down to 800-900


ive tried adjusting idle in park and drive i barely turn the idle screw and the car immidately dies


the iac was fully extended with a-b grounded i however did not disconnect the timing wire(its like 50/50 chance the intructions will tell you to do that.)


i still need to check my timing but i checked it a year ago it was only a degree off from stock

and the car has basically been parked for a yr with a random drive to a garage for some work done so i dont see how the timing could be my problem


my iac is a yr old along with my throttle body, the tps is set to .54-.55v

any ideas guys? or what other info can i give to help u help me?

 

Assuming the car is stock...

adjusting the idle screw on the throttle linkage is NEVER the right thing to do. You can't adjust idle that way. The desired idle speed is burned into the chip, so no matter what you turn that screw to, the ECM will put attempt to idle the engine at whatever the desired idle speed is for the given coolant temp. If you want to change the idle speed, start burning your own chips.

It sounds like you have another issue to me. is the IAC passage in the plenum plugged? is the IAC set properly? Also, make sure the ignition timing is 6* like it's supposed to be, not 1* off.

 

sounds like a vacume leak to me? thats what my problem was.