Vacuum Problem - 1989 Carrera 3.2L

[luigisdad]

So, finished the installation of the enlarged throttle body and the Steve Wong chip on my 1989 G50 Carrera 3.2L. Now, I have an annoying vacuum problem that won't go away.

Symptoms: Once I get the engine warmed up, above 9 o'clock on the temp gauge, the RPMs stick at 1600-1700 RPM when I come to a stop. While the engine is cold, this does not happen. As the engine gets warmer, it happens more often. Once it gets above 9 o'clock, it happens 95% of the time.

To get it to unstick (drop RPMs to idle - 850rpm), I have to engage the clutch, shift it into a gear, then take it out of the gear. Then it drops back to 850rpm.

Please, anybody, can you give me some ideas on how to fix this?

Thanks
Roy

[kyngfish]

With the changes for the new throttle body, did Steve tell you to check your base idle? Since you have an 89, the chip shouldn't have changed the idle, so it shouldn't be necessary, but I'd still jumper it and check, quick and easy.

[proporsche]

lui..your problem could be that he micro switch is not closing..here is some reading
Ivan
https://www.porscherepair.us/porsche-911-1984-1989/idle-position-switch-adjusting.html

[luigisdad]

If it is due to the micro switch not closing, would this be occurring only when the engine is warm?

[steely]

Originally Posted by luigisdad

If it is due to the micro switch not closing, would this be occurring only when the engine is warm?

I can't answer that question, but the idle switch was the first thing I thought of too.

edit: that IS a valid question of course.

[proporsche]

lui..just check it and then let us know then you can ask more Q...it takes 2 minutes to see it.You have to hear a click with the engine of.It is possible you do nor have it adjusted correctly since you have replaced the thr.body
Ivan