1987 Caviler Won't start Cold

I have a 1987 Caviler that refuses to start when it is cold. It has a 2.0 Litre 4-cyl with Automatic with 134,000 miles on it. When it starts by holding the throttle about 1/3 down and engaging the starter until it runs and doesn't die, it runs good with plenty of power. And when the weather is warm it starts O.K. I have replaced the fuel filter and it has new plugs and I changed transmission oil and filters and a new air filter and it has a new radiator and battery. I haven't changed the plug wires but the plugs are whitish when I pull them. The wires run behind the engine and down under the Throttle body. Could it be the wires or point module? Would a code reader be of help. Thanks for any advice for my work car.