I was on a trip and after 400 miles i hit the cruise back on and when it downshifted it fell on its face. Eventually could not maintain speed and had to pull over. Air temp was 85. Put fuel filter on went for a drive and it ran fine. Next day after 250 miles it did it again. Air temp was about the same. Only code was for o sensor and changed it. Drove 15 miles to interstate and it did it while accelerating. Pulled over turned engine off for a few minutes and restarted.Air temp 93. Ran about 30 mile before it happened. After several more times it went fifty miles and sun was going down. Drove through the night using ac sparingly as it seemed to help not having it on and had no more trouble.What is the problem?? Please help!