84 Carrera low speed bucking

[Raypratojr]

I have an 84 Carrera that has 102k miles. The drive train is stock. When driving in a parking lot or low speed street in 1st or 2nd gear, the car bucks back and forth pretty bad. It's mostly prevelant when my foot just barely touches the throttle. Based on what I'm experiencing, it sounds electrical. I think I've read that the AFM can cause this issue. Thanks for the help.

[917_Langheck]

Two things to sort here:

1. AFM tracks wear out, particularly right a just off idle. You will likely need to retrack the brass arms on the carbon track. There are vids and threads on that.

2. Be sure you are using an O2 meter that isn't "worn out." Porsche specs these as replace at 60k miles.

I did the first task and that sorted a bit of the parking lot huck-a-buck, but when I installed a new O2 sensor that really settled it down except for the first cold start drive, but it is only just noticable for a 100 ft or so.

BTW, some have noted that this was an issue from day one with the first motronic systems. Some aftermarket chip makers claim their program fix this mapping issue. Some others claim these chip makers are full of bunk.

Cheers

[wazzz]

Could also be the idle switch opening position in need of adjustment on throttle body. If it stays closed when slightly touching throttle, that can explain bucking.