Missfiring Seat Ibiza 1.2

Mar 20, 2019
Hi all
I am new here. Wondered if anyone could shed some light on a problem I am having.
I have a Seat Ibiza 1.2 Turbo 2015 plate - i love it! I purchased it last year after a crash made my humble Hyundai a write off.
But - It judders, randomly. I had it checked by the garage that i purchased it from but as it had 3 month manufacturers warranty left on it i have been in a constant battle with Seat Uk to fix the problem.

The garage i purchased from gave me a report stating a missfire in cylinder 4 & 2. Fault codes as follows:
P030000 Random multiple missfire
P0304000 Cylinder 4 missfire detected
P0302000 Cylinder 2 missfire detected

I took it to my local seat dealership. They said they couldn't find the fault and that it is a characteristic of the engine.
I took it for a second opinion at another Seat dealership and they told me it was a carbon build up issue due to short journeys by the previous owner - most likely. They cleaned the carbon and told me they had fixed it, but it still judders.
They had it back and completed the following, yet it still judders.
"We have carried out a number of tests and checks, including compression tests on the engine. All of these checks have shown no faults with the engine. With regard to the spark plugs we have not been able to fault them, but have changed them to ensure there are no issues with them we cannot detect. We have also changed the high-pressure pump, and swapped the coil pack. Again there are no faults with the engine, it is behaving as it should be when we test it. At this stage, we are unable to go any further, as everything is coming up as ok."

Is there any information on this fault you guys can give me? Any one else having this issue?

Many thanks


Active Member
Jun 4, 2008
South Scotland
Which engine does that car have as I know that SEAT were a bit slow in starting to use the later 16V belt driven version?

So, how to tell which 1.2TSI engine is fitted, early 8V chain driven cam engines had the turbo at the front of the engine near the radiator, the later 16V engine has the turbo at the back of the engine nearest the cabin.

Edit:- I'm guessing that the word "coil pack" means that it has a single multi output coil pack and usual HT leads going to the individual plugs.

Cleaning out carbon is a relatively big job and involves removing the inlet manifold and bombarding the inlet area with walnut shells - no possibility to "apply" any funky "carbon remover" solutions to the fuel system as all these engines are direct injection. I'd be very concerned that that car is experiencing chain stretch and the timing is now getting a bit too far out for optimal performance. These 1.2TSI 8V engines were dropped after a very short production lifetime because they were not too reliable long term, though okay if lots of bits were changed frequently it seems.

Another Edit:- if any of what I've written is true, then you need to acquaint yourself with all the possible issues with these 1.2TSI 8V engines and make sure that your local SEAT dealership understands that you are aware of these issues and that might just force them to re-engage with sorting out that car. Contact SEAT UK and let them know what is going on, when it started and what and which SEAT dealership has been involved since this car became your property, also ask about all previous warrant work on that car, they should know about that as they would have paid for it.
Last edited:
  • Like
Reactions: Legojon
DPM Performance