Hello

I have obtained a 2001 Tiburon from a relative. "Fix it it's yours" type deal. I discovered there was no fuel pump action happening, tested for power all came back as a faulty pump so I replaced the pump. New pump in and the car runs, everything appears to check out. However, heres where it gets confusing... Took it on a test drive, drives great except for two times in my 10m drive where the rpms dropped by about 1500 and then picked right back up. As if no fuel was present. Got it back to the relatives house, parked it. Tried to start it to move it. No start, but cranks. Leave it alone for a minute, then I go back 10m later starts just fine. Move it forget about it. Thinking nothing of it I'm ready to take it back to my home. Drive it roughly 5mile, arrive at a stop sign and it cuts off, no fuel. Cranks just fine, but the pump won't run. I give it about 20minutes, crank it, and it's alive. I drive about an hour, pull into a gas station, cut it off to fill up. I'm ready to go but it will only crank. Fuel pump not working. Swapped it with another "new" pump, same issue. Occasionally it'll start and idle fine, then die, and or I can drive it around the parking lot then it'll die. Left it there brought a trailer the next day and without any issues it fired right up. Got it home let it idle and eventually it cut off. On my hour of driving it gave me error codes for crankshaft curcit A as well as multiple misfires.

I checked the wiring, were clean. No water in the lines. No leaks. I'm stumped. I'd hate to throw parts at it as I'm thinking the lack of fuel threw the codes anyone got ideas?

Thanks