exhaust problem???

[Crvk99]

i've got a 96 5.0 bronco just changed (4 spd auto) xmsn filter/fluid everythings groovy, but when i accelerate the engine revs up but my rpms stay rather low. doesnt want to shift until almot 4K rpms and i hear the sound of air coming from under the truck only when in gear and i push on the gas. my exhaust ends at the cat(no muffler or pispes) and the cat looks good from what i can tell. O2 sensor is probably going out on it as well. check engine light works but not illuminated. any help would be GREATLY appreciated.

 

[madmax]

i've got a 96 5.0 bronco just changed xmsn filter/fluid everythings groovy, but when i accelerate the engine revs up but my rpms stay rather low. doesnt want to shift until almot 4K rpms and i hear the sound of air coming from under the truck only when in gear and i push on the gas. my exhaust ends at the cat(no muffler or pispes) and the cat looks good from what i can tell. O2 sensor is probably going out on it as well. check engine light works but not illuminated. any help would be GREATLY appreciated.

What transmission?