Hi, would appreciate some input into a problem with my sons 505STi A while ago the car started running rough and despite checking all the usual fuel injection and tuning issues with these cars we failed to fix it. Then in checking the spark plugs we found that the plug in number one cylinder,nearest the flywheel, was oiling up quite badly. we then did a compression test and found that it was down to 25psi, others ok, the oiled up plug and low compresion led us to think broken rings. As a result we have just pulled the head of and surprise, surprise all looks well in the ring department although I have not taken the rings of and measured the gap in the bore yet. Does anyone have any ideas on what else might give the above symptons as obviously I don't want to put it back together, even with new rings and find the problem is still there, any help would be greatly appreciated.