Hi,

I'm probably going to buy a skoda superb soon and next weekend I'll go and look at a superb 2.0 tsi 280 4x4 sport Line, 2018 model. But I do have a few questions.

The car has around 140 000 miles and has a tuned ecu. It's being sold by a skoda garage and they give one year warranty. It's been serviced with them from new.

They told me on the phone that it drives perfectly but it does have a rough idle/misfire when in eco mode. They checked with their computer and nothing comes up. The person on the phone told me it might be because of the ecu tuning.

Anyone has an idea ? I would think this could be a problem with a injector or coil but I don't know the engine.

It has a dsg 6 speed transmission, which has been serviced according to the book. Is the dsg known for giving problems at higher mileage ?

Does a sport Line trim have shift paddles as standard or is this an extra option ?

Thank you,

Edited 2 December, 20252 Dec by Daanio

You’ll have paddles - pretty sure that’s standard as part of the DSG; if not the 280’s will.

Would be good to find when the plugs and coils were changed.

DSG is DQ250 - wet clutch 6-speed. Should be good with regular servicing which is oil changes every 40k miles? So should have had 3 by now if on 140k.

Not sure on the rough idle being because of the map per se - if it was something that was there all the time then hopefully the previous owner wouldn’t have left it on there. Unless there’s a tolerance within the map that isn’t compensating for something that’s changing.

If you’re not bothered about the map (always something you can sort in time) I’d ask them to reflash the ECU back to standard and see if that cures it.

You then know for sure and can go from there…

Well for me it's a plus that it is already mapped because if not I was planning to do it as well. And it seems strange that this is causing the problem. But also strange that a skoda garage doesn't know the problem so maybe they are right. I should try and find out who mapped it and see if they can ask the previous owner. I did find something online about camshaft adjuster magnet but I know it's just guessing.

If the software is causing a rough idle or misfire I’d avoid the car completely.

No idea how long it’s been driven like that.

Also, if caused by the Mapping, it’s a shockingly poor calibration. And again vehicle should be avoided.

If the dealer can’t solve a misfire before selling the vehicle, I’d avoid them as well.

At this stage it’s just identifying variables and knocking them out until you get to the right one.

Biggest one is the map. A techy person would be able to tell if there’s a way of reading the map file and identifying the origin. Otherwise, V5 for the previous owner I guess - can’t be a data breach if it’s on the V5 (which I think the last owner is?).

Maybe the spark is retarded in Eco mode and it’s slightly out of kilter and a weak coil/plug is causing a rough idle? It’s all speculation until you start changing things.

Quick google also brought up:

Edited 2 December, 20252 Dec by travs

There’s always the option of walking away from a car with a bit of a history; if you’re looking to put money into one then starting from a decent vanilla point is always worth considering. 

Yes very true, it's like a lottery ticket I guess but same goes for a newer or lower mileage car. I don't know yet if I will walk away I'll go and see. Honestly. I'm doubting between this one and a bmw f11 528i. The skoda garage told me again that it's because of the mapping but they don't know who did it and when, but they will ask the previous owner. Previous owner told them it started doing it since the tune I can check with the tuner if necessary, or put another tune on it.

If so, could a bad calibration cause damage to the engine or injectors ?

let them flash original ecu software and then see how it works.

i would not ever buy remapped car. mine is remapped but when and if i will sell it i will do flash original software.

that car probably have missfires, which can be seen on diagnostic tool.

they probably lied.

Edited 3 December, 20253 Dec by imart143

Depends what the issue is - fuelling, spark, timing, fuel/air ratio (just guessing elements that the map would/could touch).

For me, I’d get it off asap. There shouldn’t be a compromise. I have a RacingLine map, no issues. Plenty of other off the shelf maps are the same - otherwise better to take to a reputable tuner who know what they’re doing with these engines who will tune it individually on a rolling road or out on the road.

Compared to the 528i - that might have better equipment depending on what trim and let’s face it bit better build quality etc. but it will be older, underpowered, heavier, more common, probably less legroom, definitely less boot space (bmw 560l, superb 625l hatchback/660l estate).

Also, the DSG should be remapped as well. Which should almost always be TVS.

inlet mainfold surely need to be cleaned with no doubt.. 700€

A lot of poorly set maps cause over fueling.

Carbon issues, oil dilution, turbo failure and engine failure etc etc.

Just walk away.

They are clearly not going to allow any workshop time allowance towards the car or they already would have before sale. Aftermarket warranty will refuse cover as the vehicle is modified. The dealer will fob you off and then disappear as you knew it had faults before purchase.

The equivalent 5 series is a 540i. The B58 unit is solid and easily tuned as well.

Both will be solid vehicles as long as you choose the right one.

Well, they tell me the car drives perfectly and they are giving one year warranty which is a plus, but of course when the moment is there and there are no fault codes I know they will not touch it. Also because the problem was known.

I'm guessing they will only get the map off after it gets sold, because lets face it, when you do a test drive in a remapped car with this amount of hp you will want it. 

Why I am doubting very much; both the 528i and superb have a 2.0 liter engine which is a requirement because of the taxes in my country. Both cars are full specced, the skoda also comes with a remote for preheating the cabin ? Also has carplay.  The bmw has different options, hud, comfort seats, etc.. but no carplay, but is also a 2016 model so its only 2 years older. Does have the n20 engine which is prone to cam chain issues which I'm not going to fix myself. 

But as you say, Skoda has so much more leg room and boot space, plus the power from the skoda will be lots higher than bmw. I love the room, the power, and the price from the car. That's why I'm really tempted. 

Let them give you a short ride.

Yes they will let me drive it, they are very confident though that it is not a problem and their reputation seems good with only positive reviews. It's not a typical car trader which buys and sells. I'll go and take it for a drive, I have to see it in person

If they won’t put any time into the car before sale, will they flash it to standard straight after sale as a customer? Factor it into your budget. Can’t see it taking very long so maybe shop around for quotes?

Don’t get hooked on the current power, if it is the map (and we still don’t know) it’s best it’s off there and you can do a decent safe job of tuning in your hands.

Otherwise the BMW could be a solid purchase but again depending on the servicing given the chain issue - delve into the servicing and see what the history is etc?

Edited 3 December, 20253 Dec by travs

I took the car for a test drive, and at idle RPM in Eco mode, Normal mode, and Comfort mode, it kind of stutters when it’s cold, like misfires. In Sport mode, when the idle RPM is higher, it doesn’t do that. After the test drive, with warm engine no more misfire at all. It also drove very smooth. The mechanic also mentioned that, during the stuttering at idle, the exhaust valves open and close as well.

They still think it is because of the mapping because the previous customer never mentioned something about a problem and they serviced it since new.

They will try and find out who tuned it and contact them to see if it's normal.

They connected the car to their computer again and couldn't see anything wrong.

Carbon build up on the valves.

Needs the intake removed and the backs of the valves walnut blasted.

Would also need the PCV checked and maybe replaced.

Edited 5 December, 20255 Dec by UndertheRadar

I was thinking about the PCV as well because that is possible without giving codes in this engine ? I read 3rd gen 2..0 tsi don't have to many problems with carbon build up or am I wrong? I don't think it's possible to do walnut blasting at home or is there a diy solution ?

Coils and spark plugs have been changed in 2022, for me that is also a long time for spark plugs. From the mileage Im guessing that is 50 000 to 60 000 miles ago

I believe a kit for walnut blasting is a reasonable option, sooner or later will get one ....

Here spark plugs are at 60K km, 60K mi sounds like a long interval.

Just get eating walnuts now!

That google search I posted mentioned carbon build-up and another poster mentioned it as likely earlier too.

Direct injection is the main issue but behaviour can cause it too - short journeys, for example.

No harm in changing the plugs and coils anyway. And when changing the coils, to get the electric plug off, fingers behind, pull forward, push tag up with thumb. I’ve wrecked one trying to understand and the above method is super simple.

You're right, I'll have to do it. Still didn't bought it yet but it was a very nice car for a good price. Because of that problem probably

Do these cars need OEM coils or can I go aftermarket ?

43 minutes ago, Daanio said:

You're right, I'll have to do it. Still didn't bought it yet but it was a very nice car for a good price. Because of that problem probably

Do these cars need OEM coils or can I go aftermarket ?

You can go aftermarket. I have a set of RacingLine in mine but I don’t think they do anything but provide a decent strong spark over a tired set than provide any sort of performance improvement though tbh.

Go with price on that one.

3 hours ago, Daanio said:

You're right, I'll have to do it. Still didn't bought it yet but it was a very nice car for a good price. Because of that problem probably

Do these cars need OEM coils or can I go aftermarket ?

As above.

Nothing wrong with genuine plugs and coils.

Several aftermarket coils and plugs available.

No real point until you reach around stage 3 onwards though IMO.

Running perfectly when warm and lumpy when cold points more towards carbon build up.

Could be contributed to by cheaper fuel, driving style or possibly the map is over fuelling at times leading to excess carbon.

Ok thanks, I ask because my Saab is very sensitive for OEM coils, aftermarket gives misfires.

According to the garage mostly euro 95 / E10 has been used instead of E5

Mostly highway miles they say.

Might get a lower price without warranty but don't know yet if I will take it, I'll have to think