XC40 B3 Core misfire repeat problems / reduced power / Engine Mgmt light (2023 registration)

[Newt]

Hi all,
After some advice. I recently purchased a used XC40 B3 Core with just over 7,000 miles on the clock.
After only a fews days of driving the vehicle was misfiring and reduced engine performance mode (limp home mode) triggered. The car has was recovered and spark plugs changed. Cylinder 3 mis-fire
Less than 5 days later the same issues occurred - car was recovered and this time injector seals replaced. The garage service team told me that the issue was carbonisation most likely caused by the high fuel/air mix caused by a leaking seal. Cylinders 1 & 2 mis-firing
Again after less than 5 days the same issue occurred - car was recovered and this another set of spark plugs were fitted. The garage service team told me that the issue was carbonisation most likely caused by the high fuel/air mix caused by a leaking seal and that there may have been some residue left that was interfering with the firing. misfires recorded on cylinders 1,2 & 4. Car collected on a Friday evening....
Over the weekend did a run of circa 350 miles and the car didnt miss a beat
Monday morning my other half drives less than half a mile and the same issue occurs. Car was collected and recovered to same garage service dept.
Service garage initially couldnt read error codes due to glitch in system. Once they gained access to the cars ECU it detailed a mis-fire (I havent been told which cylinders). They have carried out an engine calibration exercise. This involves driving the car at certain rpm (suggested at least 5 miles) for a period of time, increasing throttle to 4k rpm for a short period and then using 90% throttle. Apparently the vehicle also has a self-clean mode at 2700 rpm. Being an auto very rarely would the rpm stay for any period of time at 2700rpm. I was advised to run the car in manual gear selection every so often to ensure there is no carbonisation build up and to burn off any that might remain. This I did challenge as being far from ideal and it shouldnt be down to the customer to perform such processes. THe car does regular runs to and from work (20mile journey each way speeds ranging from 30 - 60 mph). I also queried why there was a self clean mode as surely this is evidence that there are known issues with the engine.

Questions I have really are related to others that may have had similar issues & what if any outcome/solution has fixed the issue.
I have had the car 6 weeks and the garage has had my vehicle for more days than I have!

[ChrisLF]

There have been reports of misfires on other threads but I don't think there was any causes fed back and the dealers/Volvo didn't know what was causing the problem after trying spark plugs etc. as well!

[AldridgeAndy]

What fuel do you use? Supermarket or a premium brand!? E10 or E5?

My car prior to my XC40 was a Ford Fiesta, I’d always run it from new on E5 from Shell, Sainsburys or Tesco. At 18 months old, my car had to have a software update at the dealer and I was leant an identical car, even down to mileage and colour. I was running the courtesy car on E10, and I’m guessing that had been the fuel it had received to date. The difference in performance, refinement and overall sound were astonishing. That sort of cemented in my mind to use E5 fuel going forwards.

[Tom33]

The same problem for my B3 MY24. No solution since December 23

[Felindre]

Been running my B4 on E 10 as long as it's been the default and never had an issue with it.

[ChrisLF]

The same problem for my B3 MY24. No solution since December 23

Have they lent you a car?

[Andy40]

I’m not one for throwing in the towel at the first opportunity, but I think if I was in your position, I’d be seriously considering rejecting tge car now, you’ve done your due diligence and allowed them every opportunity to repair it, but it’s still doing the same thing - personally, a 20 mile journey each way at various speeds is enough to get the car warm

[GRAF]

There have been reports of misfires on other threads but I don't think there was any causes fed back and the dealers/Volvo didn't know what was causing the problem after trying spark plugs etc. as well!

This doesn’t sound like the same issue. I get the odd misfire, and once when cold, and booting it on to a dual carriageway, I got turtle mode but it cleared after 30 seconds or so. It’s certainly not right, but doesn’t persist or require recovery. It also doesn’t seem to happen when the car is warm (FCVO warm as we don’t get engine temp gauges).

As to being told to run in manual at higher revs occasionally, so was I - in my case it was to ensure burn off of residue in the GPF.

Unfortunately modern engines, designed to strict emissions standards, often seem to have issues and direct injection petrol engines do get carbon build-ups.

[ChrisLF]

I do find the advice from the dealer to the OP to run the car at higher revs now and then to be questionable. As you say, beneficial for the GPF but not for deposits on the inlet valves as increased temperature won't be enough to burn the deposits off and may infact bake them on harder.

I know that defective seals have been identified as the potential problem and I hope that is the case because engines shouldn't be suffering carbon build-up problems at that low a mileage.

I wonder how the Volvo self-clean mode works - perhaps that is just regen of the GDF and nothing to do with the valves?

Direct engines are more prone to carbon/oil build-up but if correctly designed shouldn't have any problems until significant mileage has been covered.

[Embers]

My XC40 B3 Plus is now with the dealer for the 4th time with this issue. Random misfires across all cylinders.
1st fix and 2nd repair replaced plugs
3rd repair replaced spark plugs, oil and oil filter change
Actioned rejection of vehicle which was refused.
Problem quickly occurred again.
4th repair oil and oil filter change
Collected car after 4th repair and the next day it went into limp mode within 5 mins. However, this time the bonnet/car shook presumably the engine was having some sort of episode but which alarming. Car collected and taken to dealer.
Re-opened rejection application .
For me the limp mode has occurred at the same junction which has a minor incline and leads onto an A road.