erratic starting

Intermittent ,a technicians least favorite word . I dunno how many times I've cringed hearing that dexcription or reading it on a service ticket. So many variables in your case all I can offer is a few things to consider that I ha e found to be the cause in that Era amd make of vehicle . It's a short list aND may jot even be any of them .a lot of help I know but it literally could be 1000 things causing the problem. Coil pack module ( where the could packs mount to they were usually the cause of start/no start problems ). Map sensors even tho they seed to be fine and noT sowing a code they would just cause havoc of all sorts of issues Inc. The occasional no start . Ignition switches with Vats chip would also be a major player in the start/no start intermittent Olympiad. Explanation of V.A.T.S. Vehicle Anti theft system ..on the ignition cylinder their are two small this orange wires attached that connect to the Ecm which identify the chip in the key .these wires would become strained and barely make contact over time some times they would tell the Ecm it's ok to start other times they would not see the chip and the car would not start . Completely random . That would be my first chk. Have your mechanic look it over .note ...sometimes it would trigger the security light indicator in the dash clutter ,sometimes it wouldn't I'd visually inspect the actual wires they are at bottom of steering column 2 orange wires terminating at a connector . Attempting to start the car while wiggling them around would give you an idea if that was the priblem sometimes they would just come off in your hand because they were near broken anyway .Good luck hope this helps

Thanks for the help. My car is a 1990 and doesn't have a VATS system but the other info I can pass along to my mechanic. It all still hinges on the car misbehaving while at the mechanics. sigh