The Workshop Manual does not really explain the crankcase ventilation very well. The crankcase isn't really ventilated so much as vacuumed. There is a small amount of manifold vacuum applied to the crankcase from the cold start valve to the oil filler cap. Refer to D:06:02-:03. If the engine is worn and the valve seals and rings are worn then the engine could have so much blow-by and leakage that the manifold vacuum cannot even keep it at atmospheric. In such a case the seals would leak. Refer to D:06:03 System Repair Notes A and B. There is a small fitting on the cold start valve that a hose connects to and runs to the oil filler cap. This has a metering orifice. If it was replaced (changed) and is bigger or smaller (or even plugged) it would affect the way the motor runs. Am I the EXPERT checksix3 is referring to? David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxxxxxx, "checksix3" <jetjock11@xxxx> wrote: > >>Beg to differ. Had terrible vacuum leak where passenger valve cover > overlapped timing chain cover (mating surfaces not quite flush). > Steady pin point stream of solvent would kill engine. If that isn't a > vacuum leak don't know what is.<< > there is data. Port a vac gage into your valve cover and measure > it...or maybe the guy whose the expert on idle speed control can > expalin it to us. ;)