> I know that having a bad hall sensor was causing the engine problems, but I > am not sure why it made the tach jump around. I know it is an electronic > tach but I thought it took its signal from a sensor on the transmission. I think the tach is driven by counting coil pulses? -- Huw Powell http://www.humanspeakers.com/audi/ 82 Audi Coupe; 84 4kq; 85 Coupe GT