My '15 PW has done the same. I usually notice at the worst time, bumper to bumper traffic going 40-55. First stop is light peddle pressure, building to moderate followed by a near panic stop. No throttle and little time between. The panic stop has little to no boost. IDK why, I guess from learning to drive in a manual brake car, my leg is usually in a possition were I can provide full leg strength and get the job done.
OK, guys - it's been awhile since the stealership told me everything was OK - BUT IT' S NOT OK - THERE IS SOMETHING SERIOUSLY WRONG!
This week I had a chance to test the truck in the mountains (~7800 ft elevation) where I first experienced this issue.
In the attached photo I am the only person in the truck, 1/2 tank of gas and about 150 pounds of stuff in the bed - i.e., very light load. The truck is idling in gear ("D") and at the position shown I CAN'T STOP IT! I have the brake pedal mashed to the floor yet I roll all the way down to where the driveway flattens out to the road before I can stop. It's hard to see in the photo but the pitch at this point is about 40 degrees (80% grade).
I made sure to cycle the brakes a few times before I headed down - so lack of vacuum, etc., is NOT the cause.
THIS IS SERIOUS SAFETY ISSUE! If I had a load of firewood in the bed or a trailer behind me I would be out of control.
I have not noticed any issue when driving on flat ground - and I hope I never do - so this seems to be a problem with pitch or maybe the ABS system.
Can someone who has access to such a step grade please try your truck and advise the result?
My truck only has ~6700 miles on it. Brake pads are factory. Dealership tested it (on flat ground) and said it was per spec!!!!