Went to Georgia several weeks ago and on the way back a problem developed. The temperature was in the mid 90's and I had just stopped for a fill-up. Started noticing a miss under heavy load or aceleration. I was cruising at 70 on cruise control and everything was normal, except when I came to an higher than usual grade or acelerating hard at any speed. Thought I might have gotten some bad gas, so I burned most of that tank and filled up with the best I could find. This was after the weather had cooled down and the problem disapeared. I thought the Problem was solved...next morning, everything still OK...until the temp climbed up to the mid-90's. Same thing. Got home and changed the air filter and added some Heat to the gas. Cooler weather had returned and everything was ok. Again I thought I had found the problem. Several days later the temp climbed to the mid-90's and the problem came back. It acts exactly like a bad spark plug, but wouldn't that trigger a check engine light? I have no code lights at all. Plugs were changed less than 2k ago, but I'll pull them and check anyway. Anyone have anything similar or ideas???