Hi Everyone,
My 993 has a problem that I just cannot find a reason for. Most times after you start it, cold or warm, it will run fine for about 4 or 5 seconds, then start to surge, just as if you had pulled the choke out! It does this for between 10 to 30 seconds, then runs perfectly.
I have had the car 6 months, and carried out a full service a couple of months ago with new plugs, air filter, fuel filter, drive belts (genuine Porsche) distributor caps and rotor arms. It has just had a new clutch and DMF but the fault was there before this. The previous owner replaced the plug leads last year. I have replaced the DME relay, and checked the various temperature sensors. I have checked all pipes for tightness in case of vacuum leaks. When the car is surging, the resonance vacuum motor opens and closes the resonance valve. I have cleaned the Idle Control Valve which wasnt that dirty. A readout at the Porsche main dealer failed to locate anything. I dont have a fault code reader (could I build one?) and the car is a european (GB) version which I believe doesn't have a check engine light.
Any thoughts?
Mart
First holiday with the 993 - Loch Lomond, February