View Full Version : Passing gear problem

October 5th, 2014, 09:40 PM
My 1994 Lincoln Continental Executive lately giving me hard time when I go up hill or trying to pass another vehicle...I have to put the gas pedal almost all the way down to engage the passing gear! Can anyone give me some hints what is wrong!


Desert Stallion
October 6th, 2014, 01:57 AM
First thought is TPS (Throttle Position Sensor). This sensor is located on the throttle body of the engine, and is really a very simple critter, three wires, one is 5V from the computer, one is ground, one is signal output from the sensor back to the computer. Inside the sensor is a simple pot which essentially changes resistance as you rotate it. That changing resistance alters the incoming 5V into a different output voltage (signal) to tell the computer where the throttle is at. ie, at rest/idle the TPS usually reads ~1V, and as you press down on the gas pedal and the throttle blade opens inside the throttle body, turning the pot inside the TPS, the output/signal voltage increases to something over 3V.

What happens is this pot gets dirty/corroded, and may not change resistance smoothly or at all as it fails, so the computer has no idea that you're pressing down on the throttle pedal and ergo doesn't send a downshift command to the transmission.

To test, you need an analog multimeter/voltmeter. With the TPS connected to the factory harness, you probe the ground and signal wires, and watch the voltmeter needle sweep as you open the throttle. A good TPS will have a smooth sweep, increasing as the throttle is opened. A bad TPS will have skips and jumps as the throttle is opened, and a really bad TPS may not change at all until there is drastic change in throttle position.

Fortunately, TPS is cheap and easy to change yourself with basic hand tools, if this turns out to be your problem.

Let us know what you find out!

October 6th, 2014, 04:15 PM
Yep, I would check the throttle position sensor. I had pretty much same problem a long time ago, and a new throttle position sensor fixed it right up. The part was about $30, and the installation took me about 15 minutes. (Only because of the throttle body being sideways, requiring me to remove it to get to the TPS screws. Although, in 1994, the throttle body might have faced forward, making it a 5 minute job for you.) :p

Good luck!!