help - white smoke, gas problem? Options

[liquor]

I put 20$ of premium gas (93 octane) as usual and had my car washed at Shell.
I drive for 15 mins... stop the car for about 45 min and after when i
start it again the engine is rattling like crazy and theres white smoke coming out of
the muffler. The idle is very low (below 500), the engine shakes alot, smells gas alot.
No apparent leaks. Fortunately, I was able to drive the car to the mechanic shop 2 corners away
but ill have to wait till monday to know whats the problem.

I think the water jets under the car at the car wash might have shot some water in
my gas tank cuz there is some rust spots around.

What do you think?