Over the weekend I reaplied the liquid gasket between the head and the valve cover on my friends 1994 960. He went to a mechanic to check the valve ticking, that is normal for that engine, the mechanic didn't apply the gasket and he was leaking oil. Anyway, the oil leak is gone. But three days later he calls me and tels me that the check engine light came on. The code indicated the camshaft sensor signal missing or faulty. Sure enough, the insides if the sensor were cracked. The engine ran with aretarted timing while the light was on, normal. The next day I replaced the a camshaft sensor in the back of the engine but when I started the engine it was misfiering like there's no tommorow. I disconected the sensor and the engine smoothed out, but the light and retardation came back. We checked another sensor and the same thing happened. I checked all the voltages and signals and all is correct. I have no clue what happened. This also might be important, while I was changing the gasket, my friend turned the ignition to lower the windows and the RPM needle shot to the end and got stock there for a while but it came down. Any thoughts?