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1991 964 warning lights

Electrical and Electronic

Vehicle Information: Year: 1991; Body Type: Coupe; Engine (type, size, modifications): 3.6; Total Mileage: 93,300;

Followup to my "1991 964 warning lights" problem. My car would be purring along fine when all of a sudden the engine would start sputtering and just about all the engine check lights would begin randomly flashing. I'd pull over and let the car idle for a few seconds and the condition would just go away like nothing happened. The car would then run like a clock for another 500-1,000 miles when the problem would mysteriously happen again. Also the radio would completely go off and on prior to this happening with sound distortion heard over the speakers. (this may be totally unrelated but always precipitates the event). I took your advice, had the fault codes read out and found nothing unusual. I also talked with a repair shop that deals with Porsches and other high end foreign cars and was told that they occasionally see failed alternators (voltage regulators actually) causing these sort of symptoms. Turns out, according to them, that if the alternator, that typically puts out about 13.7 volts starts acting erratically and puts out over 14 volts would cause some of the systems to shut down or act strangely. I ran my car with a voltmeter attached to the cigarette lighter socket and found output of between 13.65 and 13.75 volts when the car was running normally. But just recently the car has been acting up again, (warning lights, unstable idle rpm (1,100 - 700 rpm), engine check lights, radio cutting in/out with distortion heard over the speakers) and this time I noticed the alternator "dancing around" with output between 13.3 and 14.2 volts.My question is do you think the alternator voltage regulator is the culprit? Or is the some loose wiring/short somewhere that would manifest itself in this way? Thanks

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