Once the ignition switch is repaired, turn keyswitch to ON and listen carefully. You should hear a soft click from under the dash as Main Fuel Relay (MFR) closes, and soft buzz from fuel tank in rear for 2-3 secs, and then cut off. When pump stops, Check Engine Light should go off also.

If you don't hear any sound, the MFR might be part of the problem, however the MFR usually is a no-start condition and not drivability problem; either you have fuel pressure or not. It does not affect fuel metering to the engine.

good luck

 

Okay, just following up in case anyone else has the same problem and finds this using a search. I replaced the electrical half of the ignition switch 2 weeks ago and the intermittent miss has not been back... fingers crossed. One other thing that I did which may have helped, I had a new key cut by the numbers on the lock cylinder because the other key was so worn that the tumblers were dragging and I suspect that it was not always returning to the "proper" running position on the ignition switch. This may have been why the switch failed in the first place, although this is purely speculation on my part. At any rate all of the locks operate much better with a fresh uncopied key cut buy the numbers just like the OEM key was. Thanks to all who helped on this and hopefully we can call this one fixed.