I have 07 f150 xlt 5.4L crew cab. Just bought when idling half the time it sounds like a rod knocking just give it some gas and runs drives smooth was told possible a fuel pressure regulator, has anyone had this problem I unplugged the regulator for min and nothing happened, shouldn't it do it all the time?

 

You bought a truck that was knocking at idle? WHY?

It's probably more like cam phasers.

 

It's not a rod knocking it sounds like it once o rev it up get gas flowing it runs smooth like new

 

I got it at an auction cheap $$$