Rattle noise with low load and at certain shift points.

[cp2295]

So I have a rattle that I've been trying to pinpoint for some time. It sounds kind of like gravel been ground up or something it's a very weird noise. Kinda diesely, it's hard to explain. If I am around 2-3k it'll be prominent with very light load (10-20% throttle). Won't do it with no load and won't do it if I'm accelerating at a normal rate. Won't do it if I'm going pedal to the metal. It will do it when I shift up at around 2-3k every gear, every time.

I was in neutral just revving it and getting it to make the noise while I played around with a stethoscope and it seems to be most prominent when I'm on top of the driver side valve cover near #6 cylinder.

It's a 98 4.0 ohv so no I don't think it's the chain at all.

I read on the explorer forum the guy seemed to have the same issue with his 92 but never found an answer to the issue. My friends 97 4.0 ohv also does it when it shifts sometimes, not as frequent as mine though not as loud either. His is auto however I got a manual so maybe it's easier for me to make the sound since I can control the shift point.

 

[swynx]

Both my car and truck does this. My car is worse in fact when it does this it bogs down. If I run like 93 octane it goes away. Sounds like I'm describing pinging. But I'm not. I heard running higher octane is bad and actually makes more sludge build up.

 

[swynx]

Tried pulling that spark plug yet and see if its any different?

 

[cp2295]

We have a different issue. I'm thinking mine is valvetrain just don't know what part

 

[swynx]

Your truck has a lot of weird issues no body has answers to.

 

[cp2295]

Haha I know it's weird! But hey she runs still.

 

[Dune Runner]

Could be worn push rods. Do a search on em. Or google Ford 4.0 rattle. Mine has the rattle at idle and from what I have read it's normal for the year.