Possible Causes & Corrections:

WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.

Check ignition wires for short or faulty insulation.
Check distributor cap for moisture, dust or cracks. Finely mist spark plug wires with water to check for shorts.
Connect Spark Tester (ST-125) to spark plug, and check for adequate spark.
Check ignition system for faulty grounds.
Ensure EST wiring harness is not routed too close to wiring. EST wiring harness routed too close to wiring may cause induced voltage signals.
Check ignition coil connections.
Remove spark plugs, and check for incorrect heat range, wear, cracks, wetness, improper gap or heavy deposits.
Check for poor or contaminated fuel.
Check for improper fuel pressure.
Ensure EGR valve does not stick open.
Check ECM for proper ground circuits.
Ensure TPS does not stick or bind. TPS voltage should be less than 1.25 volts at idle.
Check for proper pick-up coil (HEI distributor) resistance.
Check for restricted exhaust system. See EXHAUST SYSTEM BACKPRESSURE under MECHANICAL INSPECTION in BASIC TESTING article.
Check for bent push rods, broken valve springs or worn camshaft lobes.

CAUTION: Grounding spark plug wire for extended periods may cause catalytic converter overheating.