1999 Ford F-150 slight knock

BEASTGREELEY

MEMBER
1999 FORD F-150
V8
4WD
AUTOMATIC
68,000 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?

Wednesday, May 6th, 2009 AT 5:21 PM

1 Reply

MIKE H R

MECHANIC
3,094 POSTS

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.

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Thursday, May 7th, 2009 AT 9:51 AM