First time post here, been lurking and reading for a long while though. The car in question is an L26 powered 05' GP with around 98K on the odometer. Starting about three weeks ago the engine was no longer idling nice smooth as usual. In gear it held about 700-750 RPM and was smooth as silk but now has a distinct miss that can be observed with a shuddering of the engine and a change in the exhaust denoting the miss firing cylinder.
What I have done in the last 60 days, the fuel pump did quit. This was an easy fix and good to go. Replaced and fuel pressure holds steady at 60PSI. Swapped out plugs, wires, ignition coils and swapped in known working ignition module. In each case no particular part has had any effect on the symptoms. A compression check has been accomplished and #1 is on par with the other 5. All spark plugs were clean, free of oil or build up causing a miss fire, no burning or signs of fatigue were visible under a magnifying glass.
Major concern here is a noise that has started to become more noticeable coming from the forward end of the engine at or about #1 cylinder. Do the Series III motors have a history of valve/rocker arm issues? I would suspect a failing timing chain set would have more of an effect of the engine in general, not just number 1 cylinder. Does any one any thoughts or ideas I can explore. Thanks.
88Ironduke
