Ron, I see you live in Imperial Beach. I lived in San Diego near UCSD when I first moved to CA. The biggest quake I've felt was the one in Joshua Tree in '99 I think. Was a 7.2 I think, with serious shaking for over 30 seconds. Didn't have my car to work on then, though. It seemed to come on slowly, so I think I could've gotten out before the big shaking happened.
Now that I'm in L.A. I've felt about 4-5 small earthquakes. They were more like jolts, as if someone picked up the apartment building and tossed it sideways a couple feet. Didn't do any damage, and I wasn't working on my car at the time, but I can imagine any of those could've toppled a car off stands if not supported properly.
I think I'll ask my landlord if I can build a mechanic's pit