I have a '67 plate 1.4TSI manual Superb, and twice now I have experienced a concerning acceleration failure. One such event took place whilst overtaking on a regular single carriageway. My recall capabilities are not good, but I think I was in 5th gear on both occasions doing around 40-45mph, and dropped to 3rd to overtake on the aforementioned occasion, whereby I depressed the accelerator firmly and whilst the care initially accelerated briefly it quickly ceased accelerating and would not increase even if I pressed down further to the kick-down, or released and depressed again. Ultimately I had to abandon the manoeuvre and pull back in. On the second occasion I was on a dual carriageway, and only dropped to 4th as the need to accelerate hard was not required, but again, the car briefly accelerated and then stopped and maintained around 50mph. I can't be sure what resolved the issue other than slowing, changing down, accelerating and changing back up. I tried accelerating again on both occasions to recreate the failure, but I could not. I also tried again subsequently under safe clear conditions, but was again was unable to do so.

Can anyone help me out with what might be going on and whether this is a significant cause for concern? I would go to my dealer, but being polite, I really don't want to waste anymore time with them.

You haven't set the max speed option on the cruise control stick by accident?

Edited 2 June, 20251 yr by Gammyleg

It's a fair shout @Gammyleg , and wish it were the case, but I have ACC deactivated.

Perhaps it’s worth getting the car scanned to see if fault codes have been registered? If they have, they might point to the problems you’ve encountered.

Thank you for the suggestion @numskull :) I'm currently code free, according to my OBD11 device.

Is it purely a max speed restriction or is it a max rpm restriction? I had the latter on my previous car, intermittent of course☹️. It was never resolved in my 5 years of ownership.

Oh man, that doesn't sound good @Gammyleg ! It seems to be speed related. The safety aspect really concerns me.

Can you drive faster than 50MPH the rest of the time? What is the fastest you've recently driven?

There is also a speed limit feature that can be turned on or off in these cars.

Edited 3 June, 20251 yr by defsix

@defsix Of course, all the way up to ~70mph. The speed limiter is not set on my vehicle.

39 minutes ago, netman82 said:

@defsix Of course, all the way up to ~70mph. The speed limiter is not set on my vehicle.

Ah, I wasn't sure.

It sounds like the limiter is intermittently set. I don't remember is it possible to set the limit and deactivate it. Say it's set at 50MPH, but turned off?