Hey i just bought a 2001 ford f150 7700 series truck a month ago or so. It has a 5.4L motor in it that seems to run pretty good. The truck only has 55K miles on it. I noticed when i bought it it had a slight knock in the motor but wanting the truck i figured it was probably nothing to worry about. Oil was clean and smelled good even though it was new. Now im hearing this knock pretty much only at idle. I can hear it more down in the wheel well more than up top under the hood. Weird thing is it goes away immediately when i touch the gas (1000 rpm or so). No check engine light, oil pressure is slightly above half on the stock gauge, and no seemingly problems with how it runs. Just kinda driving me crazy. If any one has had this similar problem please let me know what you think. thank you

 

a LOT of the 5.4 2 valve motors have that particular "noise". some people have had better luck with using an OEM motorcraft oil filter with the anti drainback valve in it. th knock supposedly also comes from the psiton skirt design being short si what i have heard. My 01 does it, the 4 2002 trucks at work do it, and they have pretty close to 200k on them.
Rich

 

Check your exhaust manifolds.
If it's not one of the above mentioned,
it could be a manifold leak.

 

Theres no exhaust leaks i checked that first thing when i looked at the truck. Just never really heard of the knocking in other fords before. Suppose i shall just listen to it closely every now and again to be sure its not getting worse.

 

I just wanted to point out, that unless Ford made a change on Oil Pressure "Gauges" by model year 2001, it's not really a gauge.

It is what I called years ago, an "Idiot Gauge". Which is like an Idiot Light, but instead of using a light bulb, a meter is used instead. No real analog oil pressure sender, instead just an OFF/ON pressure switch wired in series with a meter made to read roughly half-scale when the switch is closed. The oil pressure switch closes when oil pressure is above 7 - 8 PSI or so. And that moves the meter to its display point. Which makes the driver feel good that oil pressure is OK, and relieves Ford of having to bother with customer complaints about oil pressure readings.

So in short, if you have an Idiot Gauge, you will need to use a real mechanical oil pressure gauge to really see what pressure at what RPM.