While driving the temperature gauge drops and the engine starts stalling

2000 CHEVROLET TAHOE
260,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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WEWOS
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When driving on the highway At 65, I felt that the truck started acting weird.the temperature gauge started dropping and the truck started stalling. So I had to rev the gas to go back to normal. I would go through a bump and it would get better. After 20 minutes on the road The same problem.
Mar 4, 2021 at 8:29 AM
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STRAILER
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I would check the coolant level first then lets check the codes. this guide will help us get started:

https://youtu.be/GSE9skKnOgY

and

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.
Mar 5, 2021 at 7:45 PM
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WEWOS
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No codes thrown.
Jun 5, 2021 at 1:34 PM
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KASEKENNY
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This sounds like the temp sensor is failing or you have a connection issue.

If the cooling temp drops the PCM is going to alter the air fuel ratio and this could cause a stall or poor running condition.

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

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

If nothing turns up, I would replace the sensor and retest to see if this happens again. When you have it apart, check the connector terminals and make sure they are clean and tight.

I attached the info below on how to do this. Please run through this and let us know what happens.

Thanks
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Jun 8, 2021 at 2:15 PM