In cold weather, engine power reduced occurs. It only happens at or near idle. Temperatures need to be close to freezing.

Took the truck back from the dealer. They "cleaned" the engine and replaced a cover. One side of the engine is now shiny. Great! a few days later the truck started to vibrate, check engine went on, few other things. I Brought it back to the dealer. They installed a spark plug incorrectly. They fixed it. I didn't have the chance to see whether the oil problem was gone yet.

Engine struggling and running rough, low idle. Added gas, no change in symptoms. Continued to drive until the engine light came on. Took truck to dealership. Replaced spark plug that was misfiring due to oil contamination. Replaced valve cover, throttle body and fuel injection system cleaned. $1173 not covered under warranty.