Polo gti 6n2 misfire on cylinder 3 please help...

[maidenboy]

Right folks, was cleaning up the polo as I'm possibly selling.. And made a school boy error. Whilst giving the engine bay a spruce up, I forgot to cover electrics. And as a result, the polo developed a misfire.
It was initially on cylinder 1.. So stripped all electrical components.. I.e. injector harness, ht leads, coil pack.... I also removed the plugs(brand new ones) and cleaned them.
I left the coil, ign amplifier, and leads on the radiator over night, and hey presto, the car now starts on all 4 cylinders.
Although it seems to have a residual misfire.. If I accellerate gradually, it revs up fine, all the way to the top. But from idle, if you push the pedal down hard, it misfires and struggles to pick up momentarily.. Missing on cyl 3.. But then revs out as normal.. Plugs are new, leads seem sound(no arcing etc) but I am at a loss as it was runnning beautifully before.. So anyone have any suggestions as to what I should look at replacing??
Any help would be great, I got to sort it soon as she is my daily drive..
Cheers in advance. Dave

[Peetje GTI]

I'd start with the spark splugs, cause that would be the cheapest. Change cyl 3 with cyl 1 and see what happens...

[maidenboy]

Brand New set of plugs fitted... Strange thing is, It starts and runs fine when cold, then after 10 minutes seems to start suffering from the misfire again.. seems to be worse under load though.. :-/

[tombarrack]

This happened to me after I gave my engine a clean. I just ran it for a few miles, and that seemed to sort everything out. Mine did often misfire under load as well, but I replaced the HT leads which seemed to sort everything out.

Is the engine management light on?

[maidenboy]

No the engine management light occassionally comes on when the car is spluttering, but quickly goes again as soon as it starts firing on all 4... Only code I have have back is for misfire on cyl 3.. Anyone know if there is a different code for broken coilpacks, or could that be the problem? Strange how it runs fine when cold, but misses after 10 mins... ?

[maidenboy]

Right, Replaced out leads. Ran the car till it was hot >90 degrees and problem seems to have dissappeared..
Running sweet.. Now just the coolant sensor problem to remedy..

[nigelelliott394]

Seems to be happening to a lot of folk this winter... perhaps weather related? Or maybe even age related. These cars are beginning to push on a bit. Glad you got it sorted. If you don't mind me asking, where did you purchase the leads from and are they red?

[maidenboy]

I got some from VW Direct, Werent too bad on price, and yes they are red
Moral of the story is dont clean your engine without covering up the electronics first! even if your in a rush... lol

[poloman6n2]

Hi, I have a similar problem with my 6n2 1.4 mpi Auto . It feels like it's going to cut out but doesn't, it keeps misfiring. Someone told me to clean out the throttle body so I did so and this didn't sort it because they are electric anyway. Now someone else has looked at it and he said it sounds like it's running on 3 cylinders as oppose to 4. I really don't know what to do. The car now doesn't feel to have as much power when driving than it did before. Help please