Well this one has got me scratching my head, can anyone help me!! I got a 2000 f150 with the 5.4 and I get a buzzzin sound from the pcv valve once the truck has warmed up. I have replaced the pcv twice and it fixes it for a little while and then either it goes bad again or something else is happening. The valve flutters back and forth so fast that it makes the buzzin noise. Do I have a vacuum issue possibly, or just crappy luck with pcv valves! This also may be related to the pcv valve, when i apply a load to the engine such as going up a hill, and I have the heater on and blowing warm air, it seems to stop blowing or slow down quickly the flow of air. I'm not sure if they are related but any info would be apprectiated

thanks

 

Well, you could have a bad vacuum line going to the vacuum canister that is in the wheelwell I believe. This would let the vents try to default to the defrost mode under hard acceleration.
It may or may not effect the PCV valve.
I have had a few valves do this too. I just ignore them now.
Jimmy

 

Hmm i guess i will have to check the vacuum line going to the canister and see what i can find. The motor seems to run fine I just dont like the buzzing noise, even though its not that loud, I just don't like it.

thanks for the help

 

I have a 2000 F150 with the 5.4 also. I changed the PCV valve at 60,000 from the original which was Motorcraft to a Purolator (I think) purchased from Pep Boys. I noticed the same "buzzing" sound. The Purolator brand is made of complete metal and has a spring loaded valve as compared to the plastic Motorcraft which the valve inside moves freely. I noticed the "buzzing" sound mainly at idle or low RPMs. What I think is happening is that at low RPMs or idle there is not enough vacuum to completely open the spring loaded valve. The "buzzing" sound is the metal to metal contact from it ressonating. I ended up putting in another Motorcraft PCV valve and the "buzzing" is now gone. I believe there was nothing wrong with the Purolator valve other than is was really annoying to listen to.

 

Well I picked up the same brand (purolator) and that must be what I am having problems with. It's even the second one that i picked up. I may just go get the pcv valve from the Ford dealer then, it will probably fix my problem. Well atleast it good to know im not alone

thanks