Vehicle: 2004 Suburban Z71 4x4 180k.
So, I have an issue when the outside temperatures get warm I have a rough idle / misfire happening on start up for a few minutes then it goes away, vehicle does not throw any codes.
This only happens when the outside temps start to get warmer in the summer (Southern California), todays temp is low 80's and its happening. This happens on initial start up and also after engine has warmed up, Example: If I go out an start my vehicle at noon and it's hot out it happens. I can drive to where I'm going, turn vehicle off, then come out 10 minutes later and it happens again on start up. If I were to go start it at 7am or 9pm when its cooler outside it doesn't happen, it also doesn't happen all winter long with the cooler temps. So it's something that is affected by outside temperatures.
Happens regardless of fuel level in the tank. All fluids are at the proper level.
My questions is what could be directly affected by outside temperatures like this ?
Things I've done (all new ACDelco Parts):
1. Fuel Pump
2. Vent valve & Vapor canister
3. Coils, Plugs & wires
4. Coolant temp sensor
5. Removed and cleaned throttle body in detail
6. Mass air flow sensor
Thank you in advance !