I would have the ignition module checked .
the ignition module is under the distibutor cap
what is the wiring position for the ignition module on a 1990 Buick Park Avenue?
under the intake manifold. Only way to it is on the back side of motor. You will need a long/thin 10m.m. socket to get it off.
On the distributor.
ecm and ing. module
Begin by removing the wiring harness from your 1998 Chevrolet Suburban ignition module. Remove the ignition module retaining screws. Reverse the process to install your new ignition module.
Here is the wiring diagram:
Remove the ignition module retaining ring. Pull the ignition barrel out. Remove the wiring harness from the back of the ignition barrel. Reverse the process to install the new ignition module.
Under the hood in the fuse/relay module.
It depends on the engine. If it is a 3.3 v6, you will locate it under the 3 ignition coils. Unbolt each coil, 2 screws per coil, and the unit will be free, other than the primary wiring harness. The primary wiring harness is connected by a bolt, through the connector and into the module.
The order they go in are green, yellow, yellow, brown/white, black/pink, yellow/black, brown. I found another 1991 sunbird with the same distributor at a junkyard, that's how I found out.