I have a 1991 300 te 4 matic wagon with 112,000 miles on it. When I try to start when engine is cold, it may take 5 to 10 minutes to get the car started. After car starts it runs rough until the engine warms up. I have replaced plugs, wires, and cap and rotor but no help. Any suggestions? I was told it could be the OVP relay or the cold start injector.