1999 Ford F150 V8 Four Wheel Drive Automatic 68000 miles
I get this knocking sound after the engine has warmed up for about 5 min. It only knocks while it is being accellerated and while it is in gear. I can put it in neutral and there isn't a knock, but as soon as I put it in drive(automatic of course) I get an irritating knock. The knock also quits when when i'm going downhill and the accellerator is off, does anyone have any ideas for me?
Is it a knocking sound or a tapping sound? With what you describe it sounds like a lifter. See if you can tell what side it is comming from. Have someone in truck with the engine running and in gear. With there foot firmly on the brake and the e-brake on have then throttle up a little to see if you can hear where it is comming from. If it is a lifter you will probably hear it on one side, then you can try cleaning the lifters with some engine cleaner in the oil. There are other things that could possibly be doing it but this is somewhere to start.