ZStalker505

Flex fuel E content has been between 50-63. Car starts fine when cold, if I drive somewhere car sits for a couple hours then it cranks fine but wont fire or stumbles after cranking and dies, stumble and almost run, and I have to play with the gas a little when its stumbling to get it to slowly idle like normal. Its been hot here 90+. This weekend I drove it to work after driving around about 25 miles car sat for 3.5 hrs and I had to deal with trying to get it to start and probably had to hit the start button about 6-7 times to finally get it to run. I have only ever had this happen on a very very rare occasion twice maybe in the last year and it seemed to be when it was cooler weather before I replaced my failed fuel pump. Any ideas? thnx