2007 cupra misfire issue

[arsenalmorris]

Hi all, I’ve got an issue with my 2007 Leon Cupra keep misfiring on cilinder 3,



This originally happened about 6 months ago, a full set of spark plugs and a new injector I think was put in and this sorted this for 6 months before this came back

Since then the issue had come back again in cylinder 3. Engine has been pressure tested and this came back fine? Injector has been swapped between no’s 2 and 3 and the fault stays in number 3

Pcv valve has been replaced and now I’m struggling what it could be

Everytime it’s started misfiring it has been when car has been driven about 20/30 mins and I’m in traffic idiling and just edging forward etc.

Grateful for any advice

 

[mty12345]

Maybe a intermittent wiring problem to either the injector or coilpack? Could explain why it does it in traffic when engine is getting really hot etc. Could have a look inside the connectors and check you haven't got a pin fitment issue where the socket has been spread apart slightly