Originally Posted by 1stGenCRXer

That doesn't make a bit of difference. Driving slings the stuff where it needs to be and heats up the fluid and gas so that the tire will increase pressure, until you can add more air.

More food for thought: Fix-a-flat works by slightly melting the rubber inside the tire into a goo that can fill whatever hole you have. It is possible to have a tire patched after you've used it, but generally, you should replace it if you have to resort to fix-a-flat. Driving a long time with that stuff in your tires can soften the rubber compound, shortening the life, and might even lead to tread seperation.

Seen it happen.