looking at buying a 1993 cheyenne 1500 pick up truck for cheap. apparently it runs but it doesnt have any power. any clue what could be wrong?

its a 305 with throttle body injection with about 315000 km's on the motor

 

I would first look at the condition of the throttle body to see if maybe it has alot of build up of old dirt and goo that has accumulated over the years then check the spark plugs then the air filter if it has been sitting for extended periods of time the gas could have gone bad check the timing and finally if all that hasnt fixed your problem do a compression check if you do have low pressure check the valves it is possible that the retaining nut on one of the valves could have worked itself loose I know that it isnt very likely but I have a 1992 K1500 350TBI that it did happen to keep me informed

 

My truck lost power about a year or so after new exhaust was put on. It turned out to be a crappy cat. So I took my exhaust apart and now the "cat" is just a hollow tin can basically on my exhaust.