The fuel pick up suggestion was a very good one, but half a tank was probably sufficient to say it's not a pick up problem.
Have you checked for any diagnostic codes? Your '92 can probably be read using a simple jumper wire and the Check Engine Light.
I think GM fixed their bad Mass Air Flow (MAF) sensors by '92, but that would be something to check as well. Tap lightly on the MAF with the handle end of a screwdriver or similar and see if that causes any perturbations with the engine. Also inspect the intake air tubing to see if it may be getting stretched if the engine rocks from a bad engine/transmission mount.
-Rod