bjohn--did you replace the coolant sensor for the gauge or the one for the injection system? If you replaced the one under the #2 intake runner, that's just for the gauge, has nothing to do with injection or starting. When you say you pump the accelerator, does the car smell rich after starting? Try starting it with the pedal held to the floor. Remember, there's no accelerator pump like in a carburetor. If pumping it helps, it's because you are letting more air into the intake. You need to see to that diagnostic code first though.

DS