my Jimmy will start and run great from cold start. once it gets up to normal operating temperature around 210 it starts to idle erratically and wants to stall as if it is running out of gas. I have to keep my foot on the gas to keep it running. once it stalls it takes about an hour to cool down before I can restart it. I have already changed the fuel filter, gas tank, fuel sending unit, fuel pump (twice), both fuel vent valves. checked all gas lines. I have also monitored the fuel pressure with a guage by connecting it to the fuel pressure valve. unfortunately I was never able to get a reading of it while the problem was occurring. I also put a new catalytic converter and entire exhaust system on it. I live in Florida and it never happens while it's raining so I know it's temperature related. also when it does start to act up I can hear the fuel pump whine constantly. I hope that is enough info to help me as I am a 28yo cancer patient who breaks down almost every day on the way to and from my treatments. if you need further info please feel free to ask.