Morning All,

Quick one for you today... I have reason to suspect that the PCV valve on my 122 (B18D) might be bad and causing a good portion of the tuning and poor fuel economy problems I've been fighting for months. Are PCV valves all the same and can I just pick up a generic one and throw it on there? The one that's on there now rattles when I shake it.... shouldn't there be a spring inside it to keep the plunger properly biased to one side?

In a nutshell, there seems to be a vacuum leak somewhere but damned if I can find it. So far I've cleaned and rebushed the carbs (and installed new throttle shafts), put new gaskets on everything including head and manifold, and sprayed water, carb cleaner and propane while listening for a change in rpm/smoothness. Just when I was about to give up and go sulk for a while I threw a vacuum gauge onto the PCV port on the manifold (disconnected the PCV line) to see if maybe the vacuum was low due to bad valves/valve guides (which shouldn't be the case as the head I just installed supposedly had been rebuilt fairly recently). The vacuum looked good and behaved properly when blipping the throttle, but the engine seemed to run better with the PCV disconnected and the port plugged (either capped or with the vacuum gauge installed). So maybe this is the root of the problem....

Thanks,

-aric.