94 Bonneville 3.8L won't restart 'sometimes'

[gosling]

My 94 Bonneville 3.8L still runs great (at 150K miles, 245K Km) except sometime she won't restart, e.g. after a fill-up. The problem is intermittent - only happens at the worst possible times (of course). Then after about 20 minutes (and a few nasty looks or gestures from other inconvenienced by this curse), she starts just fine.

During one of these stubborn fits (I've noticed), the tach needle doesn't move 'at all' when cranking - stays dead on the pin (electrical?). Hence, I can even tell when it's ready to start agin, because the tach needle come up to about the 500 RPM mark when cranking (as it does normally) - and sure enough, away she goes as if nothing happened - except that I've totally lost of my mind (again) by that point.
I'm real concerned I'll loose my mind one day - and it won't come back.

Thought it might be a cracked circuit board (ignition computer?) that faults when hot (e.g. no air from movement) - that might also explain why 'sometimes' (more rarely) she stalls when driving - and then won't re start - a real treat that one. But computers are pricey - hoping for some moral support in the form of experienced knowledge?????