car - 2015 Skoda Octavia VRS DSG Petrol

Hi all, 

I'm after a bit of advice if i may ahead of taking my car down to Skoda to sort out an issue.

So i bought my car in October 2021, (Then mileage - somehwere around 40k as i had the garage do the major DSG service before i bought the car).

November 2021 - EPC light came on under heavy acceleration, felt like a misfire. when i took it to WhiteSkoda in Cardiff, the diagnostic did in fact show misfire on cylinder 2. (see image below)

February 2022 - EPC light came on under heavy acceleration, felt like a misfire. when i took it to WhiteSkoda in Cardiff, the diagnostic did in fact show misfire cylinder 1. (see image below)

now: PC light came on under heavy acceleration, felt like a misfire. i havent taken it to skoda yet but have an OBD2 port scanner/reader and it is showing misfire on cylinder 3. (see image below)

given the frequency of these misfire issues:
 

1. is this just a common issue on these cars, do i need all spark plugs and/or coil packs replacing?
2. is this engine just on its say out, should i ask for any kind of compression test?
3. how can i tell if it's a fueling vs spark isssue? should i ask them to take a look at the fuel injectors too?
4. as i have an extended warranty (with some excess to pay unfortunately), is it worth getting any kind of premium/high performance spark plugs to cope with this? or would they void the warranty even if fitted by skoda? also are they even worth it?

 

it is strange because aside from this issue the car runs like a dream.

 

For context I work from home like 4 days a week so it isnt driven a lot other than to local shops/gum which is about 10 mins away. i mostly drive it slow like a granddad with some spirited driving, averaging about 30-32 mpg.  

 

oh yeah and current mileage is 55k

 

any help/advice would be appreciated as i dont want to keep sinking money into a car i assumed was fairly reliable. 

Simplest first. 

 

How long have those spark plugs been in?    as in Time / Miles.

 

were they replaced @ that 'Major Service' @ 40,000 miles in 2021?    Major Services are no guarantee of plugs or air filter replaced, or even the Air Filter inspected.

(There is no Major DSG Service, just a Service @ 40,000 miles.)

 

The spark plugs need closely inspected and the gap checked.

Edited 29 May, 20233 yr by toot

At a guess i would say they haven been replaced, ill need to dig out the paperwork, cant find anything to suggest otherwise yet.

I'll have to get back you on that as busy at the moment. 

Quick question. the car has had the EPC light come on twice (under heavy acceleration). but a stop, engine off and off gets rid of the light. 

I have a family holiday next week. As when i have driven the car there is no issue under mid/low load, do you think it fee-sable to drive my car for say a 2 hour drive each way to the holiday, just cruising or am i asking for trouble?

to clarify, the car is showing no symptoms under light load whatsoever and the epc light is off. is this likely an issue that will get worse fast or could i chance it and drive to holiday with a fair amount of confidence nothing will go wrong?

sorry that should have said "havent" not "have", cant find the edit button

 

Looks like they did change the spark plus back in 2021....damn that doesn't bode well.

 

Also my bad, thought it was a major dag service, you are right it's just an oil change.

I’m having similar problems myself. 2015 MkIII vRS petrol, manual 90k miles at OEM standard (no mapping etc). I’ve owned the vehicle since new.

 

Only recently began, misfire under moderate / heavy load, but a little more gas brings on the EPC light. Once EPC on, the engine runs with a pronounced shuddering. Turning the car off and then back on resets the vehicle. Seems to be getting progressively ‘worse’ (or it could be that I’m just noticing it more). 
 

I’m not so great with in-depth understanding of the vehicle: I’ve had it serviced annually. Had the water pump changed at 70k miles and been battling with the usual coolant / oil issues. Not sure if any plugs or coils have been changed, I haven’t kept the service records.

 

tristan, did your issue get resolved? Anyone have any pointers before I go to my mechanic? I’ve got what I think is a pretty reliable one with good familiarity on VAG cars. 
 

cheers

Hey Tristan, 

 

Is is anything like what’s described in this thread? 
 

 

On TSI (petrol) cars; the issue will probably be coil packs that fail.  Generally recommendation - 120k miles - replace the coil packs as they will start failing.  Replace all four at the same time.  Spark plugs generally are replaced every three years on average and as they are iridium, they cannot be gapped.

On TDI (diesel) cars; the issue will be the heater coils that will start failing.  Again - between 120-130k miles - replace them as a set.

Thanks Varaderoguy. I’ll probably get the guys at the garage to swap out the plugs and coil packs (assuming no other areas for investigation come out of the diagnostics). Anyone got any rough guide to how much that will set me back?

The TSI 2.0engine is a great lump. I purchased a set of plugs a couple of years back and they set me back about 65ukp for a genuine set of Iridium plugs. I think the coil packs are about 300ukp for a genuine set.

Thanks for this varaderoguy. Faulty igniter found in cycliner 1 so replaced the whole pack. Was running sweet until this morning when...the clutch pedal is now sticking to the floor. Suspect slave cylinder gone unless anyone knows a good way to diagnose between it and master?

On 15/01/2024 at 13:23, varaderoguy said:

On TSI (petrol) cars; the issue will probably be coil packs that fail.  Generally recommendation - 120k miles - replace the coil packs as they will start failing.  Replace all four at the same time.

Thanks @varaderoguy, Is there also a time element to coil pack failure, or is purely a mileage/use issue?

1 hour ago, EnterName said:

Thanks @varaderoguy, Is there also a time element to coil pack failure, or is purely a mileage/use issue?

Its generally age and/or mileage based.  The failures are caused by constant heat/cooling cycles and this is why they fail after a certain period.  I would do them personally every 5 years if driven mileage is low or every three years if driven mileage is high.

On 16/02/2024 at 22:11, alkaseltzer said:

Thanks for this varaderoguy. Faulty igniter found in cycliner 1 so replaced the whole pack. Was running sweet until this morning when...the clutch pedal is now sticking to the floor. Suspect slave cylinder gone unless anyone knows a good way to diagnose between it and master?

oh dear - that is bad luck.  The seals fail eventually, but this is not bad to fix.  You will need a new master or slave cylinder (depending on which one has failed) and a brake fluid change too.  Typically fluid change every three years.