Intermittent stalling at idle when warmed up

Welcome to 2CarPros.

It sounds like a bad crankshaft position sensor. When they get hot, they can fail. Take a look at these links:

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

If you feel these links mirror what you are experiencing, here is a link that shows how one is replaced:

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Here are the directions specific to your vehicle:

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2003 Jeep Truck Liberty 2WD V6-3.7L VIN K
Procedures
Vehicle Powertrain Management Sensors and Switches - Powertrain Management Sensors and Switches - Computers and Control Systems Crankshaft Position Sensor Service and Repair Procedures
PROCEDURES
REMOVAL

Fig.8 CKP - 3.7L

pic 1

The Crankshaft Position (CKP) sensor is mounted into the right rear side of the cylinder block. It is positioned and bolted into a machined hole.
1. Raise vehicle.
2. Disconnect sensor electrical connector.
3. Remove sensor mounting bolt.
4. Carefully remove sensor from cylinder block in a rocking and twisting action.
5. Check condition of sensor O-ring.

INSTALLATION
1. Clean out machined hole in engine block.
2. Apply a small amount of engine oil to sensor O-ring.
3. Install sensor into engine block with a slight rocking and twisting action.

CAUTION: Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder block. If sensor is not flush, damage to sensor mounting tang may result.

4. Install mounting bolt and tighten to 28 Nm (21 ft. lbs.) torque.
5. Connect electrical connector to sensor.
6. Lower vehicle.

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Let me know if this helps or if you have other questions.

Joe

Welcome back:

Honestly, in most cases the engine light would come on. However, there are conditions related to a bad crankshaft sensor that will prevent it from turning on. The best thing to do is this. If you have a live data scanner, check to see if there is an RPM signal when it won't start. Or, check to see if there is spark to the plugs when this happens.

If there is no spark or no rpm signal, my first suspect would be the sensor I mentioned.

Here is a link that explains how to check for spark:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Now, the coolant issue is a concern. Also, if the intake is leaking, you should be able to see it along where it mounts to the engine. Also, if it has a rough idle there could be a vacuum leak. Check that too,

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

The coolant usage could also be related to a head gasket issue. Take a look through this link.

https://www.2carpros.com/articles/head-gasket-blown-test

Here are a few links to help with finding the leak,

https://www.2carpros.com/articles/coolant-leak-symptoms

https://www.2carpros.com/articles/radiator-pressure-test

Let me know if any of this helps.

Joe

Welcome back:

You are very welcome. Let me know the results or if you have other questions.

Take care,
Joe

Welcome back:

Sorry for the delay. I had to make an unexpected trip this weekend.

Just make sure it is tight. If it isn't exactly 21 ft/lbs don't worry.

Joe

Welcome back:

You are very welcome. I'm glad it's going for you. Let us know if you have questions in the future.

Take care,
Joe

Welcome back:

The camshaft sensor doesn't need replaced at the same time. Did the check engine light come back on? Were you able to retrieve any codes?

Let me know

Welcome back:

They can be a nightmare, so I totally understand your thoughts. I do have a question. Was it the cam or crank sensor you replaced two weeks ago? You indicate both. Also, interestingly, a bad crankshaft position sensor may or may not set a code. Have you reinspected the part you replaced? Is there any evidence of a corrosion issue at the plug or wiring? If you remove the sensor, does it look like anything was toughing it? Also, closely inspect the wiring to the sensor. Something could be wrong with it and because you moved it around it worked for two weeks but is once again failing. It's interesting that it is acting the exact same way.

Let me know. Let me know which sensor was replaced. At that point, I will see if I have directions to check the sensor itself. You may have been the lucky one to get a bad part. LOL It happens to me all the time.

Joe

Are you able to keep it running if you stay on the throttle a bit? If so, lets check for a vacuum leak. Also, pay attention to the oil condition and if there is any white smoke from the exhaust.

Here are directions for checking for vacuum leak. Also, I will add a link for testing for a head gasket and one for pressure testing the cooling system to see if it could be related to the coolant issue you mentioned earlier.

https://www.2carpros.com/articles/radiator-pressure-test

https://www.2carpros.com/articles/head-gasket-blown-test

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

Let me know what you find.

Take care,
Joe