1991 Pontiac Sunbird 1991 Sunbird Starting Problems

I have a 1991 Pontiac Sunbird with 164,000 miles on it. Recently, I have had trouble starting the car. It will crank, but will not turn over. At times it will start and run perfectly fine until it is shut off and then it will again be hard to start. I've recently had the radiator and the water pump replaced, and I suspect that there is something wrong with the head gasket, as there will be air released when I take off the radiator cap. Today when I attempted to tackle the problem, I noticed that there was no spark when I pulled a plug wire off. I had the ignition coil checked, and was told it was good. It was suggested that it might be my ignition control module, but that should make the car run rough. When I do get it started, it runs perfectly, except for the temp gauge fluctuating. The engine is a 2.0L with TBI. When running, there is no check engine light on, and the plugs and wires were replaced last year. Any help would be appreciated.