Anybody with the 2021 Powerboost having a problem with a sudden jolt while stopped with foot on brake. Usually happens after around 8 seconds--not every time you stop. Feels like some one bumped you in the rear end - ?? Seems to do it more when its cold in the morning and less after it get thoroughly warmed up ???? Had the latest update and took it to the dealer and its still doing it after I got it home.

 

Is it your engine shutting off?
Could be a feeling when it switches to electric mode.... since you say this is powerboost related that is my thought.
I have a hybrid car that has a noticeable feeling when the ICE shuts off.

 

It's your aux pump on the transmission. Huge thread on another forum site about it. Get it in now bc the part is backordered several weeks. I have the issue currently and am awaiting the part (week 3 here). I recommend driving in tow haul mode or shifting to neutral. It only happens when in electric drive mode and full stopped. Tow haul doesn't go into electric mode so that will solve it for now. I prefer just shifting to neutral. You can also make sure you don't complete stop... keep inching forward at a super slow roll.

Good luck.

 

You are awesome!! Thanks for the reply! You would think the dealership would read these post and know what to do--but no--they have no clue. Just keep it a couple of days , download software and tell you it fixed. Thanks again!! BO

 

Mine has done this before at a red light- I have 5.0 with 3.73 rear end. Its very strange when it happens- like somebody bumps you from behind. It does not do it all the time- only a great once in awhile-- pushing 11000 miles on truck

 

I was told its your aux transmission pump (if yours is a hybrid). If you keep it in tow/haul it wont do it because the engine never shuts down--- my replacement pump at the dealer is ordered-takes around 6 to 8 weeks to get one in --good luck

 

my 21 with the 5.0 will do what he’s describing also, feels like someone tapped you in the rear end sometimes when stopped at a light. I’m probably going to wait till the trans guess or trade it at 60k. The way this thing shifts doesn’t give me confidence

 

I have read some about the 'slip yoke bump' and wonder if this issue may be that. Next service appt I will definitely mention this

 

My aux pump just arrived today. Ford is finally getting some supply in after being back ordered forever.

 

Just an update on my 4 x 4 platinum '21 powerboost hybrid with 18,000 miles --Dealer would not order an auxiliary pump for the bump problem, BECAUSE Ford said we would have to replace whole transmission instead. Claims they aren't sending out auxiliary pumps anymore.Transmission has been replaced. So far, no problems.