Hello to all:
My cousin bought above mentioned car and it has a very high idle 1500-2000 rpms.
Now, I have pulled a "51 code" prom error.
I cleaned the IAC. there is a high vacuum coming from the port that is located in TBI. When I put my finger in the hole, the idle drops nicely.
My concern is if it is the IAC or Computer itself. The light would flash like a "strobe light" when he first got it. After using the paperclip method to pull codes and pulling fuse, the ses light is steady lit.
Motor runs fine off idle.
ANY suggestions as to where the problem lies?
Thank you in advance!
Blessings

 

I checked voltage at iac connector A/b and c/d . No voltage present, so I blocked IAC passage with a towel for now to bring idle down. Car runs great other than the idle problem that was there.
Also, i tried moving plunger by applying 12 volts to a/b and c/d terminals, i felt a lil movement, but the plunger never moved in nor out.
Blessings

 

Test the IAC by measuring the resistance of the coils. There won't be any "voltage" at the pins unless the ECM is telling the valve to move open or closed. It's a "stepper" motor..... the ECM sets the 'counts' and valve moves one step at a time.

This is for a 4th Gen, but may be applicable to your 92:

http://shbox.com/1/iac2.jpg