Slower acceleration after a service

[JonRGV250]

Dunno if the case here but something which annoyed me back around 2011 or so was dealers doing software upgrades which included the changes that were made to the latest version of the car where the normal driving mode/profile has been tweaked to behave more like an eco mode - probably due to emission scandals, etc. I'd imagine a 2020 car already had anything like that if applicable though.

That still happens.
When I was a tech a Merc main dealer over the last few years they were carrying out the voluntary emissions recall and flashed the ECU.
The customer had to sign the recall paper to get it done and a lot of people came back in after having it done complaining of poor MPG.
The same happened to my mother with her Skoda Yeti and said the fuel economy was worse afterwards.
The emissions recall does relate to diesel cars though and the OP’s car is petrol.

 

[Rroff]

Think I got the date wrong a bit there was probably a bit more recent - what with the pandemic and moving house and stuff my perception of the years is a bit off lately.

 

[Conscript]

This isn’t a thing. Fuel trims are done on the fly and there is absolutely no learning involved. They follow a fixed map.

Anything that may get reset with the battery being disconnected would have zero noticeable impact on anything to the driver.

It was my understanding that there were long and short term fuel trims, and that some of the parameters for one of them were stored in volatile memory which meant it could be affected by battery disconnect, but I'll submit to anyone who knows better.

Regardless, I can attest to throttle pedal issues being a thing. Disconnecting the battery on my car would apparently cause the ECU to need to relearn the travel extent of the pedal potentiometer. The result was that the pedal would feel laggy and have a dead spot at the top, and it was immediately noticeable. After several miles it would improve (or there was a procedure you could do to mitigate it by just operating the pedal through its full range of motion a few times with the ignition on before starting the engine), but until that happened the car would "feel" slower accelerating just by way of needing more throttle input than usual. I thought it might explain what the OP was experiencing....but it's a long shot as I didn't know if they'd disconnect the battery for service. I imagine most would if they were touching anything electrical.

 

[Gaygle]

I'm assuming this was done at the main dealer? If so, they may have done a software update on the car, which, depending on what it was, can make the car have less power (if it's to "tweak" emission figures etc - it is a VW afterall)

 

[V F]

I'm assuming this was done at the main dealer? If so, they may have done a software update on the car, which, depending on what it was, can make the car have less power (if it's to "tweak" emission figures etc - it is a VW afterall)

Sometimes I don't know what to make of cars today with all their electronics. I can see the positives at the diagnostic side to see what has been going on but overall the trust in electronics in machines always blows my confidence compared to 90s cars. Even cars in the early 2000s didn't feel like mini computers.

 

[Resident]

I would ask for a refund, there’s absolutely zero reason to change them at that mileage, same with the air filter.

You should be changing your air filter every 12-15,000 miles. 13,000 is in that bracket.

Mine gets done every year and I barely do 7k.

 

[muon]

The OP says 2020 vehicle and this is the first service. So it's possible the VW long service schedule changes a few more things on the first service.

Although the link below even under a flexible service says the first one is only an oil service.

Buy a Service Plan | Volkswagen UK

Purchase a new Service Plan for your Volkswagen vehicle. Browse our different plans online today or find your local Volkswagen Retailer.

www.volkswagen.co.uk

The other possibility is that the car is on a fixed service regime (annual) and the OP skipped a service.

As for the OPs question. New spark plugs always make any car I drive feel different and then you forget about it.

 

[JonRGV250]

You should be changing your air filter every 12-15,000 miles. 13,000 is in that bracket.

Mine gets done every year and I barely do 7k.

Main dealers don't replace air filters every 12-15k miles, nor is there any reason to.
Total waste of money.

 

[Rroff]

The emissions recall does relate to diesel cars though and the OP’s car is petrol.

Good point - all the vehicles I'm referring to are/were diesels.

 

[Dr Who]

Spark Plugs are changed at 2 years, but I am wondering why it didn't have a service at 12 months if this is first service after 2 years?

 

[Black Noir]

It may be his first car, but could be the car's 2nd (major) service if he is the second owner. In which case, I wouldn't say it's particularly heavy handed for spark plugs, air filter etc to be changed if it's a main dealer and that's what is defined in their major service.

That said, if it's only done 13k miles I'd have tried to argue against it or gone elsewhere.

 

[teenwolf]

Sounds like an ecu flash

 

[Hades]

Was about to ask whether there were any software updates. I bet there were (due to a "recall" for emissions etc)..

 

[Cheetah Designs]

I'm (at least) the second owner.
It wasn't done by a VW dealer - the garage was found through a recommendation (that I trust)

Sounds like it could be a software thing...

 

[red eye]

Engine Flush?

This is a main dealer?

They sell a flush and fuel treatment as part of a “major” service at around £100 more than a full service at one national chain. they also top up tyres with nitrogen cough dry air cough which is £1 a tyre, the compressor is full of water and the water trap is on the ceiling so inaccessible. At Mr ****, don’t know about mr clutch lol