2017 oct 1.4tsi dsg no noticeable issue with car engine running. 

Main dealer changed spark plugs, still codes states miss fire cylinder 4,they now as don't know saying possible dirty fuel....... Any thoughts

I cannot see dirty fuel being a cause of misfire in just the one cylinder.

Was the misfire there before the plugs were changed?

Yes it was

Suggest checking cylinder 4 coil pack, if that checks out OK, possibly a faulty injector. 

The dealer checked  this, told me all OK.... All voltages in the correct parameters.... Hence the fuel issue.... Have to start going the v power route lol

Very much doubt that using V power will make any difference - in any case, poor fuel would affect all cylinders.

Did they actually have the coil packs tested off the engine? 

1 minute ago, Warrior193 said:

Very much doubt that using V power will make any difference - in any case, poor fuel would affect all cylinders.

Did they actually have the coil packs tested off the engine? 

Don't know, only what they've told me

Mrs Gaz's 1.8 Polo has a barely discernable misfire on cylinder no.3.  The fault code clearly shows it's a failing coil pack, and which one.

 

I stand to be corrected, but I thought misfires were only measured by spark, and not fuel? 

 

Gaz

I cleared the faults then filled it up at shell....... Feel like I been fobbed off... As car  still has warrenty..... 

 

1 minute ago, pwee said:

Feel like I been fobbed off... As car  still has warrenty..... 

 

I think you are too - take it back, as they haven't fixed it.

 

They could swap the coil pack onto another cylinder.  If the fault moves with the coil pack, it might help identify what's going on.

 

Under warranty though, so not really your problem.

 

Gaz

To confirm condition of suspect coil pack, it could be moved to a different cylinder - if misfire moves to that cylinder, that's the problem! NB. it is strongly recommended to use a coil pack extractor.

Edit - ^^^^ what Gaz said.

Edited 27 February, 20251 yr by Warrior193
added information

Watch the time, in case they're trying to delay things.  Maybe have a chat with Consumer Direct/Trading Standards, as if they can't fix it, you may be able to reject it:

 

https://www.themotorombudsman.org/knowledge-base/what-are-a-consumers-legal-rights-when-buying-a-car

 

Gaz'

Felt like they didn't want to do the work, don't they claim it back of Skoda.... So not like it costing them anything. Going to phone a vw specialist up and see what they say....... 

Is this an 'approved Skoda' warranty?

How long have you owned it?

How many times has it been back to their workshop for the misfire?

Yes, nearly 2yrs and twice 

Guard against possibly voiding any warranty by having work carried out by anyone else.  

Yes cheers 6mths left on warranty, they stated it's all noted for future, if car runs poorly..... But yeah... Lots of iffs and buts..... 

How bad is this misfire?

Not sure how advisable it will be to continue driving for too long if mis is noticeable.

Edited 27 February, 20251 yr by Warrior193
typo

Don't notice any issues with car, Vcds throws a code up..... 

37 minutes ago, pwee said:

.. Vcds throws a code up..... 

 

Do you know what code it is that comes up?

 

Gaz

 

P0304 code

 

Quite a good explanation:

 

 

If you put the P0304 code in the search box on here (top right), there's one heck of a lot of reading material pops up 👍

 

Gaz

Could have carbon build up on the valves, worth taking the manifold off and investigating 

SmallUpdate

Let the car run down with fuel, filled up with a full tank of vpower(nearly fainted at price lol) drove home cleared all faults... Driven car as normal. Checked for the fault codes yesterday and to my amazement there wasn't any fault codes.

So not sure what's going on....

sounds like potential excessive carbon build-up in that case. I would recommend taking the car on a spirited long run; let the VPower do its stuff with cleaning EGR, valves etc. Don't be afraid to use all the ponies at your disposal. You need lots of heat in the engine to let the detergent really clean up the combusion chamber etc.