I have replaced:1 injector which was # 1(was reading 3 on the ohm reader)
The Coil
Tune up- plugs, cap, rotor
The ignition module
Radiator


When I drive the car after a long drive, it does not want to start on the first crank. The check engine light comes on and my tach goes back and forth. Many times before I was able to rev the car and it would eventually idle, but tonight it would not catch. Also when I am trying to start it, it backfires just a little. Before I replaced the injector and fixed a vacuum leak, the car had no power. Now it runs real strong when it is running. What could it be?
What does the TPS do?