This engine noise has been happening for about the last 40K miles The truck has 188K miles on it and runs fine.It goes like this,start the engine cold and drive for about 5 minutes until it warms up. At a speed of about 55mph click it out of overdrive and the RPM will be about 2200.I then hear a metallic clicking sound,like detonation(though its not that).Increase the rpm or decrease it and the noise goes away.It used to only happen at about 2100 rpm but now happens around 2100 to 2400.Its hard to pinpoint as it only happens when you're driving it and the noise resonates down the truck with no specific location(other then being somewhere in the engine.I have checked for exhaust leaks ,loose heat shields etc and all is fine there. Can this be a timing chain or tensioner problem or water pump bearings.The water pump I will replace this week as it is due for replacement anyway. I surely can not be the only f150 owner who has had this problem.I can fix it if I know where it is,I just don't want to be replacing stuff I don't need to..any ideas guys?

 

Sounds like the driveshaft to me.

 

Exactly what I was thinking, universal joint.

 

Ill check it out but there is no vibration at any time.just that strange metallic sound in that rpm range.Also doesn't happen when the truck hasn't warmed up yet.Hopefully that's it.

 

Not likely that its a water pump. Could be a soft lash adjuster or as you mentioned a chain tensioner among other things. The metalic clicking sounds like a U joint as we already suggested. Sometimes you get a vibration sometimes not but you're right that is one of the indicators of a bad joint. Since it only makes the noise while you are driving it the tendency would be to think its a drivetrain component. It's the easiest thing to check at this point. If its not that then we can move on to the other possibilities. Take care.

 

I had the same type of problem (noise), it was driving me nuts.
Thought it was the e brake and hardware falling apart.
Took everything apart, lubed up the adjusters, cleaned everything.
A couple days later, same noise again.
So then I checked the u joints on the drive shaft, seemed very tight, but I doo a lot of winter towing so I figured I would change them.
Bingo, after I took the shaft out, I was trying to move one of the joints and it made the same sound, after taking them apart, I am supprised it did,nt blowup on me.