NEED HELP!

[powerstrokefan1]

i have a early 99 f350 making a screaching noise(from the exaust) when gas held at a steady position. it doesnt make any noise untill about 1400 rps and quits at about 2100. does this when i am driving and when its in neutral. wot it makes no noises and has no difference in power. took it to ford dealership where it stayed for a week...they said they fixed the problem...well they didnt any suggestions?

mods: hypermax chip straight pipe k&n air filter

[Dietoremain]

checked the turbo wheels?? ditch the k&n too.

[codysweat]

maybe the ebv is closing? ?

[carolinaboy02powerstroke]

Screaching? Like metal on metal? If it sounds more like a ton of air or a jet taking off coming out of the exhaust, it's the EBPV closing trying to help warm the engine faster. Does it only do it when it's cold and when it warms it goes away?

[NCHornet]

The EBPV will sound like a loud hissing. We usually see a lot of posts on this as soon as it gets cold. At 2000 rpm the valve opens and the noise goes away. Hope this is what you are describing. Kind of hard to diagnose without being there.

[powerstrokefan1]

it sounds like a jet is taking off and a loud screeching noise like medal on medal. and yes it quits about 2000 rps took it to a friend today whos a diesel mechanic he immedietly said it was the ebpv. thanks for the help

[carolinaboy02powerstroke]

Glad you got it straightened out. The EBPV needs regular cleaning. NCHornet's write-up can be found in the tech files.