Pj1998

I have a 2004 5.4 FX4. Recently my truck started making a static like noise when I floored the pedal and now it does this whenever I accelerate quickly. It does this in park and while driving. The closest thing I can describe it is if you’ve ever heard brake rotors being turned in a shop or an old car that’s radio would rev a static noise along with the cars acceleration. I wouldn’t call it a grinding sound but closer to an accelerating static or a scrape. My mechanic told me he couldn’t determine the cause without really tearing into things or spending a lot of time on it when I had it in for an oil change. Any clues on what it could be?

needsmoarturbo

It does this in PARK also? Things that come to mind would be something belt driven like the ac compressor with a bearing going out, or a problem with the flexplate possibly.

I would maybe have a helper rev it while you listen with the hood open maybe you can at least get an idea what area it's coming from.

Anything drivetrain related I can think of wouldn't make noise in park unless it's internal to the transmission.

Pj1998

Yes it makes it in park. I just tested and it seems that the noise starts at 3000 RPM and gets more noticeable as RPMs go up

WolfMxbee

does it sound like it’s coming from under, around the transmission or in the engine bay? Also when the truck starts, does it turn over right away, another possibility could be the starter is still engaged, seen it happen before

Pj1998

definitely from the engine bay and towards the back of it. I don’t think it’s the starter because it’s not really a grinding noise. Just a really soft scrape or static

techrep

iTrader: (1)

Fly wheel ? torque converter ?

needsmoarturbo

I'm thinking possibly something with the flexplate, or exhaust / converter rattle.
I suggest the op go under with a rubber mallet and tap the cats listening for any rattle and check for any loose heat Shields.

Jimboy

Could be heat shields but if not, I would take it to a reputable transmission shop and let them have a listen, hopefully they will let you listen also (while its up on the rack). My local Goodyear dealer does a good job identifying strange noise issues.