AGG Mild Misfire

[javalin]

Morning all,

My 8v GTI (AGG engine) has had a intermittent misfire for a while now - it improved when I changed the O2 sensor last year.  When its "working" its brilliant to drive, but when its missing it noticably shudders and feels lacking in power.  Particularly noticable at low RPM - i.e. < 3k, and trying to pull away.  New plugs, leads, dizzy + cap, air filter, CTS and relays last year.  No air leaks that I am aware of.

Whilst it could be many things - If I had to guess I'd go for either a dodgy injector or possibly the MAF??

Any thoughts?

Thanks,

James

[rubjonny]

disconnect the plug from the lambda and try, if better replace lambda. if not pull plug from maf and try, if better then maf, if not problem is elsewhere

ideally get it plugged into vag-com, see if ecu is moaning about anything. ecu relay worth changing as common fail and dirt cheap

[javalin]

no errors last time I looked on VCDS and i've already replaced the O2 sensor.  Will try with MAF unplugged for a giggle.

Ta

James

[rubjonny]

coil may be worth a look, crank sensor may also be at fault sometimes they get an intermittant fault but ecu dont log anything which is helpfull

[javalin]

Hiya

>ecu dont log anything which is helpfull
yeah.

Crank was new last year too - old one's cable had burn't away :-(

Just tried with MAF unplugged - car started and ran ok till it got warm-ish (closed loop?) - then it would just die from idle and misfire (vibrate) while running.  Plugged back in and back to normal....

Surely coil would be a more consistant fault?

James