Low Sound When Hitting 50mph

would anyone know what might be wrong if when im driving. (doesn't matter if engine is warm or cold)When I am at a stop light and i step on the gas and put the pedal to the floor, it doesn't pick up it goes at a steady pace. this is with overdrive on but it still doesn't matter with the overdrive off. It shifts 2 times before coming to 50 where it just shifts and the rpms drop really low, and it makes a low tone when it drops. what may be the problem??

 

please anyone??

 

alot of things.....air filter, injectors, cat, theres tons of stuff dude check the simple and easy crap first...hard to see whats wrong when i cant see the truck

 

thanks, i know it is not the air intake or the filter cause i just changed the filter, but for the cat, it could be that, because i have my engine light on, and the code says that it is low emission from the cat, i had one replaced, but i think it was the wrong one, so thanks for the reply ill check into all those.

 

Whats the update on your problem? Did it go away?

 

no it doesn't do it all the time, i mean it does it once in awhile and it pisses me off, because if i am the first one at the light it take forever for it to pick up