I recently bought a 1990 accord lx. A couple mornings later it didn't want to start. It was first cold morning we had. After about five minutes of trying it finally started but it ran like crap until the engine warmed up. When engine is warm it starts fine. I have checked fuel and firing. It's getting fuel and firing at spark plug wires (the spark from wire is orange not blue). I'm thinking the coil is going bad. Any help or tips diagnosing this will be greatly appreciated. Thanks.