1980 sc maf?

[biggtbiggt]

I have been fighting with the herky jerkys on a new to me car. It is a 1980 911SC 3.0 The car had been sitting for a 3-4 years but had been run a a few hrs every year. When I got the car it had a severe up and down idle problem and severe herky jerky. I have replaced the spark plugs and leaned it down with the 3mm. I think I have the startup idle under control and am pretty close on setting. The po said he had overfilled the oil and it is still missing a bit and feels like my harley did when the maf was bad. I was wondering if this car has a sensor that could require cleaning and where it is located? Thanks in advance ...Tracy

[Bob Kontak]

No MAF sensor on an 80. You probably are sucking false air. That means any air leaks past the air sensor - that is the circular lift plate that is to the right of the throttle body. The air sensor (lift plate) is the old version of today's MAF.

Cool you have a Harley. You know 98% of Harleys are still on the road..........the other 2% made it home.

Seriously, there are a lot of folks that can help you out here. Look for vacuum leaks. Also get yourself some fuel pressure gauges. Do you have an oxy sensor?

[biggtbiggt]

I have an oxygen sensor but have not looked at it yet. I will have to measure the voltage output from it sometime. I have sprayed it down pretty good with propane and ether around all the visible potential vacuum leaking spots but could not find any leaks. It really slows down when I pull the oil cap off.

[Guardsred911]

Check the Oxygen sensor. I was getting the same behaviour and replaced the relay per Bob's suggestion. Runs like a champ now.

[aoncurly]

Just unplug the O2 sensor and see if your car still hunts at idle. If it stops, chances are your O2 sensor is bad and needs replacement.