Engine Performance problem
1998 BMW Z3 6 cyl Two Wheel Drive Manual 77,000 miles
2.8 L engine Misfire at approx 5800 RPM, sets CEL. Sometimes hear knocking after misfire.
Generic code reader does not read codes. Peake code reader (BMW specific) indicates misfire in various cyl, no pattern, but cyl 4 never has come up. No other codes detected.
Car runs and idles fine otherwise, even after code is reset. Plugs, coil connectors, fuel filter replaced. Coils OK. 1 can of Techtron put in tank. Fuel pressure OK, Mass Air Sensor, idle control valve, and DME (computer) OK. Air filter clean. No vacuum leaks detected.
Why only high RPM misfire? Also how is fuel volume checked?
Friday, November 6th, 2009 AT 8:27 PM