Ok so my 1994 f150 5.0 has been feeling like I have no power what so ever. I can be doing 65 on the interstate, hit a hill and by the top im doing 45 or 50. We have changed out the plugs,wires,and found out my distributor cap and button needed changed. After doing this still nothing.

We unhooked my MAF and bam, massive power increase. So we thought it was a bad sensor, went and got a replacement for a 94 5.0 and it was the wrong one. Took it back with mine in hand and got the right one. After install we hooked it up and bam, no power again, but if I unhook it I run like a scalded dog??? What can cause this?

 

Check the fuel pressure. Just that I saw this happen before and it's possible.

 

Never done this before how do I do it, and what is normal reading?

 

There's a schrader valve (like a bicycle tire) on the fuel rail. Probably has a little black cap on it. You screw a fuel pressure gauge on to it.
Key on engine off you should be looking at low 40's psi (mine's 42). It should hold that pressure for at least a few minutes.
Start the truck, it should drop 5 psi or so at idle (high vacuum). rev it a little (low vacuum) it should climb back up. The vacuum related fall and rise is your fuel pressure regulator (back of the fuel rail) opening and closing - it's vacuum operated.
Operating pressure for your truck is 30 to 45 psi. low 40's is good, low 30's or below 30 is a problem.
Truck I dealt with would barely start or not start till we unplugged the maf, but it still wouldn't climb a hill. Eventually broke down and went and got a fuel pressure gauge, the pump was only putting out 20 psi.
It's nowhere near for sure that's your problem, but it could be so that might be a good one to check and at least eliminate before you drive yourself crazy checking out sensors.

 

So if it's reading low that is the fuel pump or something else?

 

If it's low on both tanks it probably isn't both pumps (but could be), FPR or clogged fuel filter are top on the list. You can easily check the FPR but filter is more of a replace it if it's old kind of deal.