I have a 1986 buick lesabre with a 3.8L engine. I just replaced the IAC,TPS and the EGR. I left my car unattended for a short period and my brother moved the throttle idle screw and now everything is out of wack. I have a scan to for the obd I and I don't have a clue on how to re-set my throttle back to where it was before. I need a step by step instruction on how to fix this problem. I really need my car to get back and forward to work. I would really appreciate any help that anyone can offer....Have a blessed day..Thanks..Jimmy

 

Jimmy, The idle speed is adjusted by the ECM. The problem originated with the replacement of the IAC . When you replace it the correct procedure is to set the pintle on the replacement IAC to approx same dimension as the removed IAC to avoid damage to the new one. When you first turn on the ign it automatically resets the IAC for the correct position on starting. After that the ECM should control the idle speed not any stop screw. Try removing the IAC and see if the pintle was bent on installation. If so, reinstall the old one for now. If the stop screw was turned to increase idle , back it off and allow the IAC and ECM to take care of the idle speed.
Let me know how you make out.

 

Thanks for your respond....I have another question...Is it true that by driving the car at a certain speed for a certain amount of time thats what really set the computer? I was told to ground ecm for 30 seconds and than disconnect the idle air control and than adjust the idle speed.( That did not work ).....any input will be grateful...I set my tps with the scanner @ .40.......Thanks again....Jimmy

 

I have never heard of the grounding trick. A safer procedure would be to either remove the ECM fuse for 30 seconds or disconnect the battery for the 30 seconds. Then on starting, the ECM does require some time and regular driving to adapt to new driving conditions. Most of the time its a few short trips and it will relearn quickly. I cannot tell you the exact setting for the TPS until I check. Some car's settings are the same and some are different. Will find the correct setting and let you know . Did any particular setting spec come with the TPS ?