Rlee1773
New Member
Bought a new pcv valve because the old one is kind of loose. New one causes a rough idle. Put the old one back in and it idles fine? Not sure why.
PCV Valve
- Thread starter Rlee1773
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Terrorist 5.0
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Try shaking the new one, and listen for rattling. You should hear something. If not, the valve is defective (causing a vacuum leak)
Rlee1773
New Member
It does rattle. Ive tried 2 different new ones and both cause a bad idle.
RAU03MACH
Legend
Is it a motorcraft
Rlee1773
New Member
Its not. But neither was the old one and that one worked fine. Do you have a link for the motorcraft one?
Terrorist 5.0
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Interesting. Assuming they are the same dimension wise on the outside, does it have any sort of grommet it seats in? I have a 95 (5.0), and there is a rubber grommet that the valve sits in. If yours is worn out, it could cause a vacuum leak. Now because your old one seems to allow the car to run good, I suggest trying a Motorcraft one if no one else posts an answer here.
Wish I could be more help, but I got a 5.0, not 4.6. Just explaining some general diagnosis.
RAU03MACH
Legend
RAU03MACH
Legend
4.6 5.0 the same
ttocs
Forum's #1 poster
did you compare the two before install? I learned a tough lesson that anytime you can put the old one next to the new one to make sure they are the same you should. I got screwed by the parts guy handing me the wrong part and me not comparing.
