When was your last tune-up?

Did your car actually stall from this, or did the idle just go really low?

Mine tends to idle really low when it is hot outside.

Also, with a stock tach the lowest you can read your idle at is 500 rpms. The line directly above 0 is 500.

Might also want to check your IACV to see if it is very dirty, replace fuel filter if it has been a while, check to see if your air filter is dirty, and check vac lines.