This past saturday, I got the head, timing belt, cam cover, etc. all back on my 1992 960. I just had a hole in one of the exhaust valves fixed (replaced). Cranked it up and she fired and ran.

Problem now is, after about 15 or 20 seconds of idling perfectly, it starts to sputter and generally gives me a rough idle. It has'nt stalled, even while driving. The odd thing is now the tach seems to be screwy. As the idle fluctuates, the tach will fluctuate with it between 500 and 700 rpm. Then it will drop to 100-200rpm, with no noticable difference in actual engine rpm. It has even progressed to dropping down to 0 rpm, sitting there for a few seconds and darting up to 500-700 rpm, then dropping back down again.

I'm thinkin' that these symptoms are telling me that the rpm sensor on top of the bell housing is shot. (You know when the head was off I was looking right down at it). Anyways, I'm sure that I,m not the only one, to ever have these symptoms. Is there a guru out there, that can shed a brighter light on the diagnosis.

Once again, any attention shown me, is greatly appreciated.

This has happen to me and others after your type of repair. If you are lucky it is only a missed ground wire. That wire is the one located under the intake manifold, under the round bulb part. There is a tang to a bolt that holds a plastic protector to the wire harness as it passes over the driver side engine mount. It may be only make intermittant contact. This wire leads to the power stages that engergize the ignition coils.

Best of luck

DanR 94 964 282,000 miles (48,000 on the new engine)
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DanR