Driving home the other day, 70mph, my 1994 Audi Coupe 2.0 16v.
I got a sudden judder, and the ABS light came on, for a second, then back to normal.
A few minutes later, the same happened, except this time the speedo dropped to zero, and then back to normal.
I noticed the voltmeter was reading 12v, but wavered to 8/9 then back up to 12v.
I have just replaced the Alternator, after the old one failed- in a nice normal fashion. The replacement was an exchange unit, I also noticed at the time, the voltmeter was only showing 13v, instead of 14v when running.
With the engine off, turning on the ignition to pos1. The battery light pulses dim to bright, and the voltmeter shows 8/9v.
I put a meter across the battery, and from the alternator to ground (engine running), and both check out fine, at 12.4v and 14.2v respectively.
Do any of you guys know what might be going on?
