I have a 1994 Chevy lumina 3.1 sedan. I filled it up with regular gas on a Friday. The car felt like it wasn't getting any gas so I pulled off the road about two blocks from the gas station. The car cut off by itself and would not crank. Went back to get the car pulled 3 hours later and it crunk up no hesitation or any problems. I made it back almost two blocks before it cut off again. Got it pulled home and it crunk up fine again in my drive way. I put a can of seafoam in it and just let it sit in the driveway all weekend letting it just idle and run a couple of times. Got in it Monday took it for a test drive fine no problems. Drove it to work and it drove fine no problems got ready to move it on break and it started sputtering and hesitating! Cut it off and left it there for 6 hours got ready to go home and it drove fine for 3 more days then it started back hesitating and sputtering again! Got a fuel pump and strainer 4 months prior to this and got my injectors checked, a tune up done, and Replaced a coil pack yesterday. I left the shop and it drove fine again till I got home and cut it off. I also topped the tank off with premium gas somewhere in here! No check engine light and mechanic is clueless! Help me please!