Hello all,

This weekend I was at the local NAPA store and purchased a PCV valve for my 97 F150 4.6l 4wd. The parts man was telling me how important it was to get the right one and showed me the letter "F" stamped on the metal weight inside the valve. He said that the letter code corresponded to a weight and was important to the operation of the engine.

I removed the old PCV valve (purchased from Autozone) and noted that it had the code "E" stamped on the bottom.

Does anyone know which is right and what the difference in engine operation would be?

My truck is running much better but I also cleaned up the throttle body and don't know how much difference the PCV valve had.

thanks for you help.