I recently replaced the fuel pump/sending unit assembly and have had a number of issues since. When I did the swap I had about 3/4 of a tank of fuel, so it was about a week before I filled up again. When I went to fill up, it got about 1/4 of a gallon in and started to overflow onto the ground from what seemed to be air pressure. I had to slowly add fuel (about a quarter gallon at a time) and let it settle before adding more. When I went to start it up again, it struggled to start but once it started it ran fine. I drove about 3 miles and parked (engine off) for about 10 minutes. Got back in and it started right up. Drove home, about 5 more miles and parked (engine off) for about 10 more minutes while I went in the shop to get a tool. Came out and it cranked and shook like crazy but no start. I went inside to look at the FSM but couldn't find anything. Came back out and it started first try. Now 2 days later I have driven quite a bit and half the time it starts and the other half I try, crank for awhile, wait about 10-15 minutes and then it fires right up. I went and tried adding fuel and I still have the same slow fill. Really not sure what to do at this point.