can anyone tell me if when you take off the oil cap the engine runs better at idle than it does when the cap is on. if so why is this.
ford transit oil cap
Jan 07, 2005
3 Replies
Appears to run better is more accurate, you probably have a clogged pcv valve (or crimped or leaky plumbing, clogged intake, etc.) and the release in crankcase pressure obtained by removing the cap helps the engine breath.
Pull the pcv out of the grommet and see if it rattles, if not replace it. Check the grommet, is it a snug fit? If not replace. Check the pcv lines to the throttle body are they cracked or clogged? If so replace. All of these parts will cost you a buck or two individually. Pull the pcv line off of the throttle body, are you getting vacuum? If not, it is clogged and needs to be cleaned.
My guess anyway... Matt
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