Missfire 16686 Polo 1.2 3 Cyl

[tg10002]

Hi,
Has anyone cured a misfire when hot on a 2004 1.2 3 Cyl polo ?

I have used VAGCOM VCDS Lite & The DTC is 16686 Cylinder 2 Misfire.

My first thought was coils, so I have swapped the coils over & the message still appears on cyl.2

Only seems to come on when idling & when hot.?

Any ideas ? Thanks !

[hwar84]

I'd swap the spark plug as a starter then if still No 2 you need to do a compression test. The possibility of a sticking valve is the big worry, see recent posts on this. Hopefully it's just the plug but I doubt it.

[tg10002]

thanks .. I will do that, Readiness is 0010 0101

I'm confused as that means the lambda sensor is not working even though I can see readings from it when I check the levels ?

Still the only fault found on a scan is the misfire on cyl 2.

[tg10002]

Update .. due to reading other threads I decided to do a compression test, unfortunately it revealed the issue .. most likely valve problem on no. 2 cyl. the readings were 15/10/15 BAR..

Anyone like to cost this for me ?

[enginejack2000]

tg10002
Since I do not know how to post URL's, please search google for

2005 Volkswagen polo needs new engine!

This should point you to a posting in a consumer group which contains further details on the problems and some costs for replacement polo cylinder heads.
At my last visit to my local VW garage a tech told me that when the shaky idle problem first appeared, the garage attempted to recondition the heads but failed. Presumably because recutting the burned valve seat upset the valve to camshaft clearance. So it seems the only fix is a new head and if you happen to find out what changes have been made to stop future problems, please post the info.

Incidentally, the new head on my polo has reduced the shake considerably although it is still noticeable especially when the engine is cold.