CEL = Check Engine Light
There can be stored codes even if it's not on.
The TPS is at the end of the throttle shaft to measure it's position. It is a potentiometer and the the middle of the three contacts in it's connector will change resistance between the outside two contacts as the throttle is moved. It's best to use an analog meter to check it as glitches will be easier to spot. Hook to the middle and an outside contact and monitor the resistance as you move the throttle, resistance change should be smooth. Sometimes a dead spot happens just off idle where the throttle is during cruising.
