likestrucks

I need some insight. I have an 03 Suburban. L59, 140k. After driving in hot weather, if I idle it will be normal, then the revs will drop low and it will want to stall, then it revs up over 1000 and then settles back down to normal. It does this over and over and sometimes stalls. While it's wanting to stall the gas peddle doesn't effect the chugging. It did this last summer in the heat. I changed fuel filter, O2 sensors, and MAF sensor. I have checked the fuel regulator to see if it is getting fuel on the vacuum line side but it's dry. I have cleaned the throttle body. I haven't tested fuel pressure but I don't think it's the pump because it ran normal all fall winter and spring. But now that the hot weather is back it is doing it again. No codes. No missfires being logged. Long term fuel trim will jump up over 25 on bank 1 and 2 while it's wanting to stall. Then when it settles back down the trim goes back down to around 8. Temperature sensors all show proper temperatures for everything. Does anyone have any ideas?