My car keeps stalling on idle

Welcome to 2CarPros.

This can be the result of a few different things. A dirty throttle plate can restrict air flow at idle and cause it to stall. Also, an engine vacuum leak can cause this type of an issue.

Since the vehicle runs good while driving (off idle), here is what I suggest. The first thing is to ask the car what is wrong. This vehicle has an OBD1 computer system. I will provide a link that shows how to retrieve the any codes which are stored. If there are codes, it will be very helpful. It will help eliminate guessing what component to check next.

Here is the link:

https://www.2carpros.com/articles/ford-lincoln-mercury-obd1-1995-and-earlier-diagnostic-trouble-code-definition-and-retrieval

Next, if no codes are found, inspect the air filter to make sure something isn't plugging or blocking air flow. Here is a link that shows in general how an air filter is replaced:

https://www.2carpros.com/articles/how-to-replace-a-car-air-filter

If that is clean , next, I need you to check for engine vacuum leaks. Here is a link that shows how that is done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

If you find no leaks, you should try cleaning the throttle body.

https://www.2carpros.com/articles/throttle-actuator-service

If none of that takes care of the issue, then it is going to get more involved. There is a way to actually check and adjust the throttle position sensor, which could be the problem. You will need to use basic testing equipment, so I will first provide links to help with that. After the links are the testing and adjusting procedures. The attached pictures correlate with the directions.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

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Here are the procedures for testing and adjusting.

ADJUSTMENTS
Throttle Position Sensor Schematic

picture 1

CHECK THROTTLE POSITION SENSOR OUTPUT

1. Connect the Rotunda Breakout Box 014-00322 to the powertrain control module.

2. Turn the ignition switch (11572) to the ON position.

3. Measure the voltage between breakout box pin 47 and pin 46 SIG RTN (ground).

4. Rotate the throttle linkage by hand and observe the voltage readings.

5. With the throttle valve fully closed, the voltage must measure 0.5 volts.

6. With the throttle valve fully open, the voltage must measure 4.1 volts.

Throttle Position Sensor

picture 2

THROTTLE POSITION SENSOR ADJUSTMENT

NOTE: If the voltage is not within specifications, adjust the Throttle Position Sensor (TP) as follows:

1. Loosen the TP sensor set screws.

2. With the throttle valve fully closed, rotate the TP sensor until the voltage is 0.1-1.1 volts.

3. With the throttle valve fully open, verify that the voltage is 3.1-4.4 volts.

4. Tighten the TP sensor set screws to 2 Nm (14-20 in lb).

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I realize this seems like a lot, and it can be. However, without trouble codes, this is what happens. With that, the first thing to do is check for codes. Follow the first link I supplied and let me know what you find. If nothing is found, then you need to start the checking. I will be here to help if you have questions.

Take care and let me know what you find.
Joe