Well, it was interesting to watch the road tech replace EVERYTHING; the fuel pump and sender assembly, new fuel lines, fuel filter, Injector, HEGO, TPS, and IAC. One thing he was talking about the most is water/ethanol contamination, which would settle out to the bottom of the fuel tank when parked for a day or more. Once driven it would mix in the tank and the severity of the problem would go away. He looked in my tank and really didn't see this in mine, although there seemed to be like water marks in the very bottom of the tank. He wiped it out and then filled it with premium fuel that has no ethanol. My running concern has gone away, and the unit runs really very nice now. Of course, having that many parts replaced is like a shotgun blast, hard to miss. I did end up with another electrical problem just before this last repair. it was supposed to have been fixed and was not! It is intermittent short in the main loom, (the engine loom was already replaced for another issue.) When driven on the road about 1 mile the fuse for the signal lights blows. Have no brake lights or turn signals and causes feedback in the instrument display. Hisun picked it up yesterday to take it back to Texas to replace the main loom that was supposed to have been replaced 3 months ago.
So, I guess the bottom line is check for fuel contamination. Do not use fuel that has ethanol added! The fuel pump retaining ring on the tank is really tight, watched the tech bust a sweat trying to get it off then back on, he was a very BIG dude and was using a very special tool.
You might try to get a gas sample after letting it for a couple of days in the position that gives you the worst starting problem, check for obvious contamination and then google how to check for ethanol in gas. If you find any fuel issues, make sure you replace the fuel filter.
Hope my ramblings help you.
NOD