Originally posted by dkmnx
From the accufab web site:The TPS is connected to the main wire harness with three separate, color coded wires:
1.
Gray & Red
2.
Gray & White
3.
Brown & White
The gray & red wire is the ground wire (could also be a black wire).
The gray & white wire provides the voltage information to the ECM (could also be a green wire).
The brown & white wire provides a 5-volt reference signal WITH THE KEY ON (could also be an orange wire).
If you have any problems identifying the different colors or if the wires are different colors from those described, check inside the plastic quick disconnect plug. The plug connection tangs should have an “A”, “B”, and “C” next to each tang.
A = gray & red wire
B = gray & white wire
C = brown & white wire
Because of the different suppliers of TPS’s, and the potential for different wire colors, you may need to “poke around” on the wires in order to determine the positive and negative leads. An easy way to take voltage readings is to stick a safety pin through the individual wires, and then make contact with your Volt Meter probes to the safety pins.
To check voltage, THE IGNITION KEY NEEDS TO BE IN THE ON POSITION BUT THE ENGINE MUST NOT BE RUNNING. With the positive (+) lead from your voltmeter, pierce the gray & white wire. With the negative (-) lead from your voltmeter, pierce the gray and red wire. The voltmeter should read no less than .98 volts nor more than 1.0 volts. If the voltage is too high, loosen, but do not remove, the two screws holding the TPS to the throttle body, and rotate the unit counter-clockwise, until the voltage is correct. Rotating the unit clockwise will increase the corresponding voltage. When the voltage is correct, retighten the two screws. The only adjustment is the “slop” between the inside diameter of the holes and the outside diameter of the screws, so we are dealing with just a few degrees of rotation.
The Ford ECM’s are very unforgiving when it comes to ANY engine modifications from stock. The addition of an Accufab throttle body should not have any negative effect on idle speed, off-idle performance (tip-in) or the RPM returning to idle speed, within a second or two, when the throttle is closed.
If on the other hand, modifications to the stock engine include additional supercharger boost with the use of different supercharger pulleys (particularly noticeable on supercharged 2003-2004 Mustang Cobra’s) or adding a “re-programming” chip or add-on computer module, the standard TPS voltage readings and other drivability issues may be noticeable, and could include an overly fast idle and a resistance of the ECM to “allow” the throttle to close properly, resulting in a delay between removing your foot from the gas pedal and the engine returning to idle.
These are not throttle body problems. The throttle body is a mechanical device with only one moving part. As long as the throttle body slams shut when you close the throttle (key off, engine not running), the throttle body is functioning correctly. Any other problem is associated with the ECM and the feedback it is receiving, either due to the increased boost at idle (more air supply) or the add-on computer chip sending incorrect (or unknown) data to the ECM. If you follow this and still have the problem it could be a bad tps,swap one out with a friend if you can before buying a new one.Also check the spring that attaches to the throttle body,I know it doesnt have to do with the tps adjustment,but when I installed mine the idle would flucuate even though the tps was adjusted right.The spring was to weak to pull the throttle arm all the way in at times.Changed the spring problem solved good luck.
Mustang Gods 
