Poor mileage after Manifolds replaced

[Jercan]

I have a 2020 Ram 1500 Limited. Had cracked manifolds that were replaced After being replaced I have notice a drop in gas mileage. Any thoughts or has anyone experienced something similar?

 

[BowDown]

Mine were replaced last July with the current part number, mpg hasn't changed

 

[vincentw56]

How are you calculating gas mileage? And what are you comparing to?

 

[DEG]

Had something similar happen to my last Ram. Dealer said it was because they had the battery disconnected and it reset the PCM back to the original factory defaults. They said factory defaults are programed for performance in a new motor with no component wear. As you get more and more miles, components begin to wear and the PCM automatically learns and adjusts to compensate for the wear. You will need to drive it for a while so the PCM can relearn. Might take a tank or two.