My 97 4.6L F-150 has a rattle in the engine when warm.It comes and goes and is never rattling when i take it to get checked ,everything else is good the dealership says. I was wondering if any one has had this in their truck.

 

Is it only under slight load? Like maybe 1/4-1/2 go-pedal?

It might be pinging.

Try a higher octane, like 89 first, and see if it helps. If it does, go back to 87, clean the MAF, the EGR passages, etc.

Usually, the EGR clogs up (or more accurately, the plumbing to the throttle body), restricts it's flow, and that causes the ping to start.

Other things can cause it too, but try 89 octane and report back.

 

Thanks alot ill try it and report back later.

 

Take a look at this: https://www.ford-trucks.com/forums/s...4&page=1&pp=15

 

Bdox, I don't understand how a thread on oil is relevant?

 

There was some pretty astute reporting on that thread with regard to 4.6 rattle with some oils and not with others.

 

Ahh... good point!

 

If we figure out what kind of rattle he has. Oil won't fix detonation.

 

Of course oil won't cure detonation, just covering all the bases. The sound was not well defined. He did not say under load, or any other circumstance that induces it other than 'when it's warm.'

 

I can't seem to hear it under a load of any kind.Just at idle when the engine is warm.Sorry for not being more precise.

 

That's OK. In that case it could be the oil you are using.

In the thread I posted above, Flash stated:

My 4.6 makes a lot of valve train noise with most of the oils with the exception of the Pennzoil and the Havoline. It is real quiet using those oils. Motorcraft and Mobil One 5w-20s make the most noise but the MC has, in this engine, not shown any elevated wear metals.

Something to consider, the guy has done his research.

 

yeah. i think im gonna try that.thanks

 

Did you check all the exhaust heat shields?