Whenever I floor the pedal of my 99 sierra theres a real loud whooshing noise, like air running by my window, or something seriously rubbing. Theres a serious loss of power too. I was trying to pass someone when i first noticed it, and i couldnt do it. Its like theres some kind of resistance... It started happening after I took the old girl through some serious mudholes last weekend. The only opinion ive gotten has come from a local service shop who said it could be a torque converter. Any ideas/ similar experiences?

Thanks

 

intake restriction maybe, dirt or mud clogged the intake passage or filter