My 98 Civic stalls while driving. Wait 5 minutes and it starts back up again. About a half-second before it stalls, the "check engine" light will come on. While it is dead, if I shift into park, I can't move the gear shift to any other position (automatic transmission).

I took it to a mechanic and he replaced the distributor cap. Then a couple weeks later it stalled again. So the same mechanic replaced the ignition switch. Ran great for about six months, then two weeks ago it stalled again and once again yesterday.

Any idea what's going on?

Check for codes. It's likely the Ignition Control Module (ICM) and coil, located inside the distributor, need replacing. Apply silicone heat transfer compound to the back of the new ICM.