Idle Problem

[bobk964]

I have a 1990 964 C4 with an idle problem.

Whther its cold or hot sometimes the it will not idle and cuts out.

There appears to be no pattern, is intermittent.

I have had the engine decarbonised, idle valve cleaned, new DME and new spark plugs.

Any thoughts

Bob K

[Loren]

Has anybody looked for fault codes with the Bosch Hammer or Porsche PST2 (w/round connector)?

[911addict]

Intermittent?

Could be electrical.

I had a loose connection in the engine wiring loom which was shorting sometimes. Very hard to trace, 2 garages and many hours....

All sorted now.

[magcuda]

idle valve cleaned not replaced. that is the hot/cold variable. need to scope idle valve while it is acting up

[baysidec4]

I have the same problem every time I disconnect my battery (1990 C4). You need to get the idle reset with the Bosch Hammer. My mechanic charges $75 for the job and it takes 15 minutes. The car will run perfect after that.

[systemx]

My father has a 94 964 C2 and he also has an idle problem, its fairly severe and it cuts out sometimes, Wether its hot or cold. It has been to Porsche 3 times already this will be its 4th time. On the last occasion Porsche said it was a faulty idle control valve and it had been replaced. Its been a few weeks since it went in and its back its old same self. Generally after each visit to Porsche the car would be fine, its about a 100km run to the dealership but the problem normally used to come up after a few weeks of driving. I think the car spends more time at Porsche than at home. Would anybody be able to offer any insight I have PC based OBDii scan tool but i am unfamiliar with the pinouts on the diagnostic connector and don't want to go fiddling. It will probably be at Porsche in the next few days again but I'm starting to have my doubts with them.