have a 92 s10 blazer 4wd vin w. stalls out when in drive after hitting the gas. you can reverse it just fine and rev in neutral without a problem. but when you try to drive it it coughs and dies. any idea whatcould cause this?

 

other info: it is not fuel pump.
seems worse uphill.
does not seem to rev as high or accelerate as fast as it used to before the problem.
seems worse after heating up.

just put a used transmission in before problem started. i'm not sure if this is relevant.

could this be a faulty throttle position sensor? that is what i'm leaning towards, since i disconnected it in neutral, with the same symptoms being displayed - it starts to sputter(putting it lightly)and stalls out. any ideas would be appreciated.