Causes stalling my truck is stalling when I accelerate then loses power.Its has an electric fuel pump which is a holley blue.

SOURCE: truck idles and runs fine

if it is an older model say from late 90's on down. It could be your automatic advance on your distributor is bad. This is caused by vacume leak to distributor.

SOURCE: 1985 camaro that does not crank

Stop jumping all over the place!!! 1. check for spark. If none find out why. Check for proper timing. "basiline" timing at about 8 degrees btc. MSD units are nice when they work, but if no spark, pull it out and get an old style hei setup and stick it in there for a while.(hooks up with one hot lead) 2. If spark is working, check bowl levels on carb (I do this by attaching a syphon hose to fuel inlet and opening port on side of each bowl, adjusting level so fuel does not spill out and is just below level of hole.You checked the chain...is it in "straight up"? (cam mark down, crank mark up)
Fuel pressure should not be above 7.5 lbs. in fact, for start up testing I'd lower it a bit to about 5psi. (use a gauge) That way you won't be blowing needle valve off the seat. Unless you have the valves adjusted too tight, there is no reason for it not to start!!!
Good luck!

SOURCE: 2000 Chevrolet Truck S10 P/U 2WD 2.2L , loss of power

The first thing to try is a new fuel filter. There is sock filter within the fuel tank also, but it fails less often. If the engine has lots of miles, it may need a new O2 sensor although the codes should point that out if it were a problem.

SOURCE: Old chevy 235 six cylinder, when cold it falls on its face

Question, does it stall, or bog? A few things come to mind. You say the carb. is new, what is the cfm of the carb.? Could be too much carb. for the cam. It could be a problem with the accl. pump on the carb. dumping too much fuel on take off. Have you checked the fuel pressure at the carb. also? You say you checked the timing and vac. advance, but is the timing set high enough? Usually this is a sign of too much fuel being dumped. If you have the chance, try another carb. Let me know.

SOURCE: 1978 Chevy 1/2 ton Truck - fuel is not getting to

On the front of the carburetor where the fuel line comes in is the fuel filter.Did you change that?Take off that line and slip the end into a container,coffee can size.Have a friend turn over the motor,watch for fuel.If you get fuel your needle and seat have seized in the closed position.No fuel check the rubber lines that hook to the fuel pump.You replaced the pump,it's only $2 worth of rubber hoses.If they don't seal the pump can't pull the fuel,it's cheap insurance.