Hello forum. I have an 87 V6 GT and need to know how to adjust the air screw on the throttle body to the original factory settings. Also is there a reader available for the ECM serv No 12271.867322. M721121325. Regards. Lombok

I think most will tell you to leave the idle adjustment screw alone. Very few have had luck in obtaining a correct adjustment. It was plugged at the factory for a reason. Earlier in the year, I had some issues on my 87GT and tried adjusting mine. The plug had been removed sometime prior to 2000 before I bought it. I ended up replacing the throttle body with one that still had the plug. Didn't resolve the issues. The problem was elsewhere.

Vacuum lines, idle air control, o2 sensor and the like are usually the culprit if you're getting a high idle. What is the particular problem you're trying to fix?

Idle around 11/1200 after warm up. Mine also had plug removed. Lombok

My 88 GT had similar problems with low then high idle. I found an Actron CP9690 Elite AutoScanner on Amazon. It reads OBD I, along with the computers found on newer vehicles. The cost isn’t to bad since it can be used for other cars. The unit will give codes from the ONBD I, but unfortunately will not give voltages, as stated in the Pontiac Service Manual. For kicks I looked for an old Pontiac/GM Scanner on EBay, but never found one. The codes that came up were for the throttle position sensor, and IAC, which I changed out. Next I cleaned the throttle body with special cleaner. I was afraid to start taking voltage measurements with a ohm meter while the engine was running, I terribly good at causing shorts, burnt wires, and didn’t want to fry my really old engine control. I had to adjust/bend the lever on the TPS Sensor which was pretty easy to get the correct idle.

Mine also idles at 1100 by the tach. It would warrant pulling the upper intake, but you could check out all the vacuum lines underneath. In the past, I've found a cracked line between the MAP and fuel pressure regulator that was causing some tip-in hesitation. I separated it completely, sleeved it with heat shrink tubing, and sealed it. Rubber tubing could be used to sleeve a connection, too.

Another area that also set a code 32, was the little looped hose on the EGR solenoid. On an 85Gt I had, the hose was broken but still appeared solid. Replaced it with a small vinyl hose. Problem fixed. Another EGR solenoid had a deteriorated rubber sleeve on that little hose. It was porous enough that it just crumbled apart. Again, a piece of vinyl hose fixed it.

On my 87, I finally changed over to Rodney Dickman's Stainless Steel Vacuum Line Kit that I originally bought for cosmetics and kept in the cabinet for years. I did find that some of the factory fittings were a little larger than the metal tubing and might have allowed some vacuum leaks. To resolve that, I smeared a little RTV on the ends of the tubing so that when the rubber connector was pushed on, the RTV would mushroom out, making a seal where the tubing entered the connector.

quote Originally posted by Lombok: Hello forum. I have an 87 V6 GT and need to know how to adjust the air screw on the throttle body to the original factory settings.

Ogre's Cave - bottom of the page.
http://fierocave.shorturl.com/idlestop.htm

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Lombok,

Check your personal email. Call me if you want.

Mike in Sydney

[This message has been edited by Mike in Sydney (edited 05-30-2022).]

quote Originally posted by fierofool: I think most will tell you to leave the idle adjustment screw alone.

Correct.
Many mess w/ this way often make more problems.

1. High idle can be vac leak or someone set timing wrong.
See my Cave, Vac Leaks

2. After 1 is fixed... If IAC Steps in ECM data stream and engine warm/hot is under ~ 10 or over ~ 30 w/ no load from trans (AT in Park, MT in Neutral) then check idle screw.
Examples:
If cover from idle screw is gone... likely already F'd this up.
If someone bend the throttle arm etc... fix that before mess w/ idle screw.
Either can add or remove Steps and if really bad set a number of "Codes" too.

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