Basic Ignition System Checks (C4): C(3)I: Spark
WARNING: This page does not describe the selected car, but rather 34 other vehicles, including the 1991 Pontiac Sunbird, 1991 Pontiac Grand Prix, 1991 Pontiac Grand Am, 1991 Pontiac Firebird, and 1991 Pontiac Bonneville. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect tachometer wire (if equipped). A shorted tachometer will not allow vehicle to start. Disconnect cam sensor and attempt to start engine. If engine starts, see cam sensor trouble code in TESTS W/CODES article.
Check for adequate spark with Spark Tester (ST-125). Check for spark on plug wires No. 1, 3 and 5 (one at a time). Leave matching plug wire connected while checking for spark. When removing spark plug wire from spark plug, twist and pull on boot. DO NOT pull on wire.