I have an 02' Blazer 2Door 2WD 4.3L vortec. Great truck - very low miles. Sorry if this is long, but i want to give all the info - about a month ago the fuel pump went out. She was showing signs / not starting on the 1st/2nd try and finally wouldn't start. It's a 12 year old pump and I was also that guy trying to make til Friday on a quarter tank - so no complaints so far. I checked the relay and fuse, all good there - so I bought a new AC Delco and fuel filter. Drained and dropped the tank, cleaned and dried the tank and installed the new fuel filter. The pump came with a new pigtail - so I wired in the new pigtail, attached the hoses and re-attached the tank. Not bad for 6 hours of work ( first time - don't judge ). She fired right up and ran like a champ / about a week later I stopped and filled up the gas tank. Next day - no start / no whine from pump / 0 psi at the schrader valve. Assuming it must be an electrical issue - I dropped the tank and tested the gray power wire / 12 volts. But to be thorough / in case I made a mistake / I stripped and re crimped all the connections, heat-sealed the sleeves and wrapped in all in electric tape. Tested the pump - she hummed like a kitty. Re-installed the tank and she fired up like a champ. Drove around a couple of days - stopped and filled the tank with gas. Same thing - wouldn't start right there at the pump. i poured fuel in the intake - she would start and run until the fuel burned up. no hum from the pump. had it towed home ... again ... began to siphon my now full tank of fuel to drop it yet again. At about 1/2 way , I tried her and the pump primed and she started right away. For the past two weeks I have been unable to make it NOT WORK - but i am worried to go very far , less i be stranded again. on the gauge I get 60 with the key on and 56 running. With the engine off the pressure holds for quite a long time - well over an hour+. So what would cause a brand new AC Delco pump to not work only when the tank is full - then start working when some of the fuel is removed? Anyone else have this issue or have any suggestions.