Hi, I have a 1.2l 3cyl Skoda Fabia -08 with uneven running and (high lambda value). It runs unevenly and misfires. I have changed the ignition coils and spark plugs. The spark plug on cyl 1 was black with soot. When I open the oil filler cap, it sucks in air and starts to run even more unevenly and choppy. When driving, it sometimes ends up in limp mode. What could be wrong? Thanks for reply.

Do a compression test. Don't be surprised if cylinder 1 shows low compression.

6-valve single cam or 12-valve twin cam 1.2?

Edited 1 October, 20241 yr by Breezy_Pete

Yes, I'm afraid it's the valve seal on the intakevalve that's leaking. I was hoping it would be a easier fix...

Welcome,

A mod can maybe move your thread to the Fabia Mk2 section.

 

As to removing the oil filler cap.

The cap is not just to keep oil in, if there was a vented cap needed there would be one fitted.

18 hours ago, Ejnarsson said:

Yes, I'm afraid it's the valve seal on the intakevalve that's leaking. I was hoping it would be a easier fix...

Exhaust valves are more commonly found to be the problem on these engines.