pcv valve
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Senior User
Joined: Nov 2004
Posts: 240
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From: Appleton, WI
pcv valve
hey guys i have a 2001 f150 with the 5.4 with 40,000 miles on it. I changed my oil and put in a new pcv valve. After putting it in my truck idled alot lower and when put in gear it would drop below 500 rpms, so i took it out and put the old one back in and it was back to normal. anyone know what would have caused this i am wonderig why a new one would do this? help would be greatly appreciated, thanks.
Hotshot
Joined: Jul 2005
Posts: 11,931
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PVC is positive crankcase ventilation. what this is, is basically a hose that connects the motor insides ( valve cover) to the intake manifold. the intake sucks the oil fumes out of the motor and allows room for fresh air to enter. the amount of vacuum you have is determined by the pvc valve which is a ball and seat ---backflow preventer. baasically a "big" pvc valve would act like a vacuum leak as seen by the intake manifold. you might have a slightly different pvc valve than original. see that is it made for your truck and not a general fit type.
Moderator
Joined: Dec 2001
Posts: 22,436
Likes: 17
From: Louisville,Ky.
It is probably allowing more air in than the PCM is used to and is not getting the same amount thru the MAF. You might try unhooking the battery for about 30 min. to reset the PCM. It may be ok after that.
