Car idles fine, but dies when i give it throttle, CANNOT figure out why?

alright here it goes, I have an 89 240sx with a ka24de swap, and it hardly runs, when we got it we thought it may have been a clogged fuel filter or a vacuum leak, we have tried evereything we can think of, messed with all of the timing, compression test, new spark plugs, wires, rotor and cap, we checked for clogged cat and it wasn't that, im ready to sell the car and take a huge loss because i dont wanna spend all my money trying to fix it and end up with nothing, the car will start and idle perfectly but as soon as you give the car gas it dies, sometimes it will let you give it gas and it will increase rps with alot of hesitation but it still has no power, also when you floor it, it makes a really low sound and the rpms actually go down. So you have to give it like 1/4 throttle to increase rpm. we cleaned maf, throttle body, we checked fuel injectors and there squirting, we dont know how much they should be though, the pump also comes out after the fuel filter( it just pours out, we dont know how fast it should come out either). the car has major electrical problems, the previous owner did alot of rewiring himself and there are grounds EVEREYWHERE, when you step on the brakes the lights dim and the radio turns off, i didnt think that could cause the car to act so badly, the plugs are sparking fine and teh timing seems perfect. ANY HELP WILL BE MUUUUUCHH APPRECIATED, this is the only car i have for my family since a tornado messed up my wagon!