M651 Automatic B Class - Rumble then drop in revs before acceleration

[BClassy72]

Hello All, first time posting on here.
I have recently bought a 2016 Mercedes B class B200 Automatic (M651) with around 70k miles on the clock. A problem occured with it on the road home from the garage after buying it. When driving up an incline I put my foot down only for the car to faulter and rumble for a second or so (the sound is exactly like going over rumble strips in the road) and then pick up the revs again. I immediately took it back to the garage again and they took it in for testing. I was told it needed a new battery (their reasoning stated the old one was flat so the voltage was low through the system(?)), which they replaced, and I took it again. A day or so later the issue happened again, on an incline whilst accelerating. I took the car back to the garage again and they replaced an injector and the fuel filter. A day or so later I got it back and then the following day the problem cropped up again.
Each time the issue occured there was also a smell of diesel fuel in the cabin after the event. There are no fault codes shown when the issue happens either.
I'm now at a stalemate with the garage. I'm thinking of returning the vehicle for a refund but apart from this issue the car is immaculate and the best I have seen for the money I have so I am asking on here for a bit of guidance as to whether or not this is a known issue and is easily resolved before I return it. I am able to replicate the issue where I am quite easely (hills around me) and have provided them with dashcam footage of it happening and a sound recording but they are stumped and have gone quiet on me. In fairness to them the area they are in is completely flat (1 1/2 hours away from me) and during the test footage on my dashcam they were not able to replicate the issue.
A copy of the sound file can be found here - Bclass rumble
Thanks for any help you can give me on knowing what this issue could be.

 

[DSM10000]

It needs scanning with the MB Star computer bys someone who knows what to look for and check. stored codes and to run diagnostics

 

[BClassy72]

It needs scanning with the MB Star computer bys someone who knows what to look for and check. stored codes and to run diagnostics

Thanks I'll seek someone out with one of these

 

[colinallcars]

Thanks I'll seek someone out with one of these

It will cost you, can you get the supplying garage to organise (at a location near you) and pay for it?

 

[BClassy72]

It will cost you, can you get the supplying garage to organise (at a location near you) and pay for it?

I'm going to be speaking with them Monday about this as I'm not even sure if they have already scanned it with this device. If they haven't then they have said get someone more local to look at it but I need them to clarify in writing if that is going to be at their cost or not. I did buy a warranty with it but thats limited to £1000 so I wanted to keep that in my back pocket until the supplying garage has run out of options at their cost. To be fair they have been fairly receptive but on the 3rd time of asking to take it back they have really dragged their feet in getting back to me.

 

[colinallcars]

I'm going to be speaking with them Monday about this as I'm not even sure if they have already scanned it with this device. If they haven't then they have said get someone more local to look at it but I need them to clarify in writing if that is going to be at their cost or not. I did buy a warranty with it but thats limited to £1000 so I wanted to keep that in my back pocket until the supplying garage has run out of options at their cost. To be fair they have been fairly receptive but on the 3rd time of asking to take it back they have really dragged their feet in getting back to me.

You’re entitled to return the car, might be the best option when it’s carrying a fault like this.

 

[DSM10000]

I'm going to be speaking with them Monday about this as I'm not even sure if they have already scanned it with this device. If they haven't then they have said get someone more local to look at it but I need them to clarify in writing if that is going to be at their cost or not. I did buy a warranty with it but thats limited to £1000 so I wanted to keep that in my back pocket until the supplying garage has run out of options at their cost. To be fair they have been fairly receptive but on the 3rd time of asking to take it back they have really dragged their feet in getting back to me.

The warranty you bought is irrelevant. Don't let them tell you that is all the cover you have.

They are responsible for repair costs, if they refuse then return the car for a refund.

You have statutory rights under consumer law and you do not have to rely in 3rd party warranties.

 

[BClassy72]

You’re entitled to return the car, might be the best option when it’s carrying a fault like this.

Thank you, I am rapidly coming to that conclusion.

 

[BClassy72]

The warranty you bought is irrelevant. Don't let them tell you that is all the cover you have.

They are responsible for repair costs, if they refuse then return the car for a refund.

You have statutory rights under consumer law and you do not have to rely in 3rd party warranties.

Thank you, you are right. I'll be speaking to them Monday but it feels like I'm going to be taking it back given all of the other potential faults it could be I have read about today.

 

[ALFAitalia]

......and the best I have seen for the money

.....and now you know why!!

Take it back for a full refund before your 30 days is up.
As said above the warranty is irrelevant.....its in addition to your statutory rights...not instead of. Warranties are to protect the dealer from the potential cost of repairs....not you, which it why people should never buy one if what's being offered is less than 6 months as you are covered by law up to that point anyway.