Misfire when engine cold and at low revs.

[nelson1m]

Hi I’ve got a misfire when the engine is cold and idling. It persists when driving slowly in the low gears.

After a while driving it seems to disappear. Had the coils checked all fine.
Had all brand new spark plugs. Was advised to use fortes emissions cleaner. Seemed a little better but still misfiring when idling and in low gears driving slowly.

The car has been asking for “service now” since around mid September but couldn’t afford around Christmas. Booked in for a full service on the 21st of this month.

Can anyone help? Mk5 07 on 98k

[mjmallia]

Have you ever done or had an intake valve clean, as they clog with carbon build up......this causes misfires

Checked the cam chain for stretch.....this causes misfires and a lumpy idle?

Checked the cam adjuster for wear and or broken oil rings.......this causes misfires and a lumpy idle depending on which ring broke?

Possible lazy injector issue also


All issues that arise at the 100kish miles on what I assume is a GTI.

I recently worked though my GTI and came across them all except the injectors......time consuming, but okay for a DIY'er

Drives perfectly now and improved with every step........old cars now that need that major servicing with the miles they have on the clock

[nelson1m]

That’s great thank you.

I decided to fill up the tank and take it for a good blast!

Woke this morning and turned on the engine…. No misfire. That Fortes emissions cleaner must have worked, fingers crossed!

[ZoliWorks]

Have you ever done or had an intake valve clean, as they clog with carbon build up......this causes misfires

Checked the cam chain for stretch.....this causes misfires and a lumpy idle?

Checked the cam adjuster for wear and or broken oil rings.......this causes misfires and a lumpy idle depending on which ring broke?

Possible lazy injector issue also


All issues that arise at the 100kish miles on what I assume is a GTI.

I recently worked though my GTI and came across them all except the injectors......time consuming, but okay for a DIY'er

Drives perfectly now and improved with every step........old cars now that need that major servicing with the miles they have on the clock

Regarding this, to check the cam seal rings, I assume it's enough to just remove the vacuum pump and the cam housing, no? No need to remove the chain or the VVT unit itself as the rings are built into the housing, right?

Pretty sure I have the metal ring variant, being a 2006 bwa, but I know for a fact those weren't changed so might explain why I sometimes get idle misfires. Or it could just be injectors actually..