1987 911- engine lugs like it's about to stall at 2000+RPM

[Tony Carrera]

I just moved to the Bay Area (sea level) from Las Vegas (2200 ft above sea level) and I am experiencing a hurky-jerky issue while maintaining a constant speed anywhere from 1200-3000RPM. It's not like missing, it's more like it's about to stall with the car noticeably jerking back and forth. When i let off the gas or accelerate, the problem stops and it only happens sometimes.

I bought the car from California last summer and when I took it back to Vegas, I had to have the air flow sensor adjusted because the car kept stalling at stop lights. I am guessing that now that I have moved back to sea level and to a more humid environment, I will have to do the same. Any other ideas or suggestions? If that is the problem, is that something I can do myself, or better left to the professionals?

[DRACO A5OG]

You could adjust the AFM yourself via the O2S and a DVM. If you can borrow a LM1 it would be more accurate. If you have a Bentley Manual it will help allot.

Once adjusted, you must re-adjust the base idle to 880 RPMs via the Jumper. Remember the Tach marks start at 200, 400, 600, 800 then 1000 RPMs, so just above middle of 800 & 1000.

Jim

[dhagood]

might want to check your O2 sensor, when mine went out the car would idle very slowly and would not run smoothly at constant rpm.

+1 for the bentley manual, they have a nice section on 3.2 driveability issues.

[rusnak]

It sounds like a bad signal from the crankshaft position sensor, but to be honest it's got to be diagnosed steo by step. The only reliable way to check fuel air ratio under load is with a dyno or an LM-1 tyoe of tester and a test pipe with a second bung. If you want to drive to Fresno, I can try to help......

[JerP]

Those symptoms sound like a bad head temp sensor.