So here in Sacramento it has been 100-107 degrees lately. 2 days ago, when it was 107, my check engine light turned on.
I drove around for 2-3 miles and then parked it in the garage for 3 hours after which I got back in and drove around the block. By then it was about 99 degrees and my check engine light turned off.

Is it just coincidence that the light turned on during the heat and off when it had cooled down? Has anyone else ever seen this happen and is there something else I should be looking into?

 

No, its not usual. But, maybe your spark plugs or coilpack are playing with u.