Auto Transmission Idle Drop

[SlyAttacks]

How much should the idle drop when the transmission is put into gear on a 89? Does anything control this?

[jtgh]

yes but is this a FI car or carbi?
89 had 2 engines one carbi 1 EFI .

tell us what's in the box.

if EFI (TBI in your case) the IAC valve controls idle at all times hot.

the simple test is throw on HL and Fan and AC if have it and see if idle drops hot.
if it does, IAC is not doing its job.
and there are 25 things that can prevent idle IAC , even though the IAC is perfectly good.

here are 2 things the can stop it.
1: air leaks (illegal) in to the induction.
2: ECU is running in limphome or backup mode ( caused by many things)

idle happens only when all other things are working perfect.


is your Check engine light on , at KEYON, NOSTART, then go out after start?

tell more.

cheers