Another HELP! Different issue different truck

ok so on my 81, i put in the 2002 5.3 4l60 in it. at first i ran a walbro 255 inline pump. it couldnt keep up. so i put in a aeromtoive intank pump. worked great for about 6 months. then it just randomly died. then it started up but acted like it couldnt keep up. so i changed the fuel pump again to an ac delco pump. worked great last night when i test drove it for about 8-9 miles. im like good deal it works. so i drive it to work today. works great till the last mile or so then it starts acting like theres no fuel. and it only when u give it gas in gear. at idle its fine and in park and give it gas its fine. im tired of changing pumps and im tired of not being able to drive it. its not throwing a check engine light. i dont know if maybe its a sensor going bad or a connector is loose somewhere but i would thing it would throw a code. i cleaned the ground on the frame for the pump and re ran a whole new power wire for the pump. also i dont know if it has anything to do with it but sometimes randomly the fuel gauge will read full or empty when its not full or empty then it will catch up i guess you could say to what it really is then go back to either full or empty like its getting a mis reading or bad ground. kinda like when you unplug the oil pressure sensor and the gauge goes to the max. help would be greatly appreciated.
btw im running rubber fuel hos to and from the tank. a friend used the same stuff and his truck is fine.

How is your hose in the tank attached to your fuel pump?I had mine come loose and my fuel pressure dropped to 20 psi.What fuel pressure do you have at the rail?If you are runnig the corvette filter maybe that is going bad.If you can check pressure at rail first to see what you have.Mine would idle and run fine at 20 psi but if i floored it it would break up after 4000 rpms.

Hose clamps on the connection. Its not loose. At the rail last time I checked at idle was around 45-50 but my gauge had a leak and I haven't bought a new one. And the hose isn't long enough to check while driving. I dont have the corvette filter. Im running a return style fuel rail so I have a hose coming from the rail all the back back to the tank. And mine starts cutting out way before 4000 rpm when it's in gear.

crazy question for ya. Have you changed your fuel filter? Any of the three pumps you listed should support a 5.3. If your getting that high of fuel pressure at the rail you should be fine. I think gagliano was meaning the little fuel line between the fuel pump and the assembly. Did you get some good high pressure fuel line? Its only about 3 inches long. Also make sure you use some good hose clamps so it wont blow off. Did you run a new power wire to your fuel pump? May want to do that and clean up all the connections.

Yes the fuel filter is new in the tank and a new summit filter. Im running rubber fuel hose from oreillys. And I have two clamps on the pressure and return lines at the motor and just one on each at the tank. My lines have never come off. What's this 3 inches long hide yr talking about? Also I have run a new power wire and cleaned up my ground wire.

The 3 in line i am talking about is on the sending unit inside the tank.What are you using for a regulator?Maybe that doesn't hold the right pressure under a load.

Oh im using the line that came with the pump. On both pumps I did.
Im using a brand new factory regulator on the rail.

What im wondering is could it be a sensor like the maf or iac or tps? It doesn't ever die when I give it gas like its running out of fuel it just chokes

so i checked the pressure when i got home. its running at 43-48 once i give it gas it drops to 20-30. if i undo the regulator it raises to 60 at idle and drops to 35-40 with it revved up high.

That shouldn't be.Mine with the corvette filter setup is 58 psi and when i rev it it barely moves.I would check to make sure the pump in your tank isn't leaking by where the hose inside the tank is attached to pump. If there is no leaks anywhere else it must be leaking by inside the tank.

All wires tested good voltage. Alternator tested good. Is it possible it could be over or under pressure in the tank?

It should be 56-60 psi always. It should never drop. So you're definitely looking at a pump/line/regulator problem somewhere.

That's what I was thinking. Could it be the mass air flow sensor? Or wiring somewhere besides the fuel system?

Ok seriously. I just changed the pump and the sending unit and brand new power and ground wires and grounded it at the battery. Its still doing it. Could it be anything else. I've changed the pump 3 or 4 times now and the sending unit. And the wiring is good. Its gotta be something else. Anyone have ideas!? Please!