loud sound coming from my exhaust sounds like a jet engine or something...

[POWER-STROKER250]

i have a 2000 ford f250 and since i have put a ts performance 6 pos. chip on my truck every morning that its cold or night 30 to 50 degrees outside at about 1,500 rpm or so my truck makes this loud kinda like a jet engine noise out the exhaust but if i give it more gas or let off the gas it goes away. ive been told by mechanic's not to worry about it but its kinda annoying to hear. i've noticed on warmer days where its like 70 to 100 degrees out it doesnt do it. anyone have any ideas on what this might be? thanks for yall's input on this.

[dannanw]

Winter Operation, Hard Starting, Hissing Sound Etc...

[CSIPSD]

Its your Exhaust Back Pressure Valve... Sounds like its working perfect!

[crdenoyer]

what he said

[hotprowl]

HAHAHA Mine only does that in the morning, but it's so loud, the neighbors can hear it across the street and come out to see what the hell is going on. I have the MBRP turbo back so it's super loud.

[7.3Lariat]

Mine makes a horrendously loud sound when it high idles with the 5" back. Pretty sure everyone in my apartment complex hates me.

[Tsgs69400]

I love mine, espicially with how I can make it happen on demand with my dp.