KJ, I read every page and every detail and my 2860 with 150 hours on it behaves just like yours, exactly. It’s really frustrating and I called AGCO since my dealer is unresponsive to a bunch of calls, they didn’t even bother to call back.
After that call to AGCO the dealer did an about face and wants to help, they said they are seeing several of these models with pinched fuel lines due to poor routing from the factory. I’ll know more in 2 weeks when they show up. I’m glad I found your post!
I thought it was heat related too but I have 2 bars left on the top of the gauge and have never seen a temp light come on, I did almost everything you did and it still goes lame in 30 minutes. Bush hogging took 6 hours when I can get it done in over 2. The A/C can’t keep up and the cab turns into a greenhouse. Not fun.