Hey all, about two months ago during the hot summer, my car got pretty hot one day... and after that I have a good amount of play/slop in my steering wheel. I'm talking like 5+ inches both ways before it "catches" and starts to turn the wheels.
I'm not sure how the engine temp would have really effected things, but check the rag joint in the engine compartment, and each universal in the steering shaft to start with. Mine has a little dead spot right at the center that lets it drift a bit side to side even on good roads.
Steeda and MM I believe sell a solid steering shaft (dual u-joints, no rag joints), but they're not cheap, ~$400 IIRC. Might want to get under there and see if that rag joint's about to fail or something.
Same one, actually the seller too. It's very easy to install, and with my car it made a noticable difference, especially for $35 and less than a half hour of work.
Check out the flaming river steering shaft at Summit. They are solid with ujoints and cost under $300. I've had the flaming river shaft on the car for about 8-9 years and believe me you will notice a huge difference - solid feel, quick turn ins and responsive.