05 Leon 20VT one misfire on cylinder 3 (idle) - SOLVED

[daniel_18]

Hi,

Today I started the car and after a 15 min' I came back and I let the car running on idle and I connected it to VAG-COM. I saw 1 misfire on cylinder 3 and after 2 minuts it disappeared and didn't came back.
The car has 92K, changed coilpacks to new revision, recently changed plugs to ngk bkr7eix, new cooland temp and the fuel is RON 98. Also replaced all the breather hoses.
If it matters, I did the N249 bypass.

Also, when I started the car, the RPM's reached to 2000 and then idled to 720-760.

Thanks!

Solved:
So I put Isolierband on the small cracks that on the coil wires and all the misfires disappeared. (thanks to LEE69)

 

[LEE69]

Could be the wiring loom to the coil packs

 

[Slimy]

To be perfectly honest, I wouldn't worry about it at all. You could spend ages looking, replacing all sorts of stuff and never actually see another misfire.

Wait until it's a consistent misfire, then at least you'll have something to look for.

 

[daniel_18]

If it matters, I didn't drive the car for 3-4 days, only enter & exit from the parking.

Thanks LEE69, I"ll check the wiring loom.

Still, should I need to check anything else? I'm sure that this is not normal to have a misfire on idle..

 

[LEE69]

Move the coil pack to another cylinder, see if the miss fire changes to another cylinder

 

[daniel_18]

(UPDATE)

So I checked the wires and I saw few cracks on cylinder 2&3 but it's very tiny ones.
only the isolation were cracked from what I saw.
Couple of days ago I checked again misfires and I saw 1 misfire on cylinder 2 (only when idle).
the engine was cold and it appears 3 minutes after I started the engine.
Next dau I drove the car for 40 minutes and when I checked for misfires, and nothing came up.
(all the tests were made when the car was idle)

BTW, the coils are BERU 0040102043.

 

[daniel_18]

A log I did:
http://www.sendspace.com/file/p4vsl8

 

[daniel_18]

Someone?

The tiny cracks on the wiring loom could cause idle misfires when cold??

 

[Mr OCD]

Someone?

The tiny cracks on the wiring loom could cause idle misfires when cold??

Tiny cracks?

 

[daniel_18]

Yeah, there few cracks on the isolation of the wiring loom.
http://www.sendspace.com/file/x5uq1w
http://www.sendspace.com/file/akzik4
(Sorry for the bad quality)