Check for traces down side of plug. (archive)

I have been chasing an intermittent miss for a couple of weeks now. It popped up one day, ran fine to work, 9 hours later it was running on 5 when I went home. It has gotten better since then, now it is just intermittent, after it goes off the cold start warm up period, it misses kind of like a bad lean surge when it runs off the O2 sensor in closed loop. I am guessing an injector. So far I have swapped (with used parts) the fuel pressure regulator, Dist cap, spark plug cables, AFM, ECU, inspected the plugs, which are all about the same, very clean, probably 10k old, inspected and taken a meter to the rotor and absolutely nothing changes. O2 sensor works and has about 22k on it. Anyone have any ideas?
Mike W.

I had bad miss with my truck finally found the problem was related to spark traveling down outside of plug. Leaves a fine carbon line down the outside of the plug. If this is the problem you need to replace the plug and the wire. Replacing just the wire still leaves the trace on the plug for spark to follow.

Follow Ups:

[ Follow Ups ] [ 5-series (E28) Message Board ] [ Msg. Board FAQ ]

Questions, comments, or problems, please visit the Roadfly help desk.