Intermittent Misfiring, Rough Idle, Power Loss (9n)

[xerxes]

Hey guys,
My 2003 Polo 1.4 16v has been experiencing Misfiring, Rough Idle, and Power Loss intermittently. (30% of the time)
When this starts happening the car is basically undriveable. Can't get up to speed and stalling.
Turning the car off and letting it sit for 5 minutes seems to cure it, before it happens again.
The aircon also plays a role in this as it seems turning it on will make the problem more likely to occur.
(Extra load on the engine?)
The problem is its intermittent so it's very hard to trace. I have found no way to reproduce this every time.
I ran a OBD Scan and found no codes apart from the faulty v68 motor for the air re circulation.
(Which shouldn't cause this).
I've googled and asked a few people and come to the conclusion that it is the coil packs, I tested them with a multi-meter and got 380 Ohms for all of them, which, according to this link
Best way to fully test the coil packs?! - Skoda Fabia Mk I - BRISKODA
is the correct amount of resistance.
There does seem to be some sort of after market wiring though.
This is coming off the connector of the first coil pack.
I believe this a ground wire being spliced into 4? I have no idea why this is done or if it is stock.
I haven't ruled out the possibility of the coil packs but they seem to be working fine. I've changed all spark plugs and inspected everything. I have also been told it could be a fuel problem, which I think is unlikely.
I'm a student so I'm desperately trying to figure out this problem without spending money that I don't need to.
I have also read that these engines suffer from broken exhaust valves but I do not believe that is the cause because it would not be intermittent.

Any help is appreciated.
Thanks guys
-Harry

[h100vw]

Those earth splices are std. For each coilpack.

I reckon I have the wiring diagrams for this motor somewhere. But I am GTI through and through. So no idea where to direct you.

Definitely VCDS scan would help you.

Hey guys,
My 2003 Polo 1.4 16v has been experiencing Misfiring, Rough Idle, and Power Loss intermittently. (30% of the time)
When this starts happening the car is basically undriveable. Can't get up to speed and stalling.
Turning the car off and letting it sit for 5 minutes seems to cure it, before it happens again.
The aircon also plays a role in this as it seems turning it on will make the problem more likely to occur.
(Extra load on the engine?)
The problem is its intermittent so it's very hard to trace. I have found no way to reproduce this every time.
I ran a OBD Scan and found no codes apart from the faulty v68 motor for the air re circulation.
(Which shouldn't cause this).
I've googled and asked a few people and come to the conclusion that it is the coil packs, I tested them with a multi-meter and got 380 Ohms for all of them, which, according to this link
Best way to fully test the coil packs?! - Skoda Fabia Mk I - BRISKODA
is the correct amount of resistance.
There does seem to be some sort of after market wiring though.
This is coming off the connector of the first coil pack.
I believe this a ground wire being spliced into 4? I have no idea why this is done or if it is stock.
I haven't ruled out the possibility of the coil packs but they seem to be working fine. I've changed all spark plugs and inspected everything. I have also been told it could be a fuel problem, which I think is unlikely.
I'm a student so I'm desperately trying to figure out this problem without spending money that I don't need to.
I have also read that these engines suffer from broken exhaust valves but I do not believe that is the cause because it would not be intermittent.

Any help is appreciated.
Thanks guys
-Harry

[rgvlee]

I had rough idle and what seemed like misfire on my gti recently
Gradually got worse
No noticeable power loss though
Ended up being an air leak from a breather pipe on the inlet manifold

[xerxes]

Hey guys
Apparently using my diagnostic cable without changing the baud rate to 9600 only lets it scan a few modules
I just re scanned and found three more codes
3 Faults Found:
16687 - Cylinder 3: Misfire Detected
17953 - Throttle Valve Controller: Malfunction
17604 - O2 Sensor Heater Circ. Bank1-Sensor1 Electrical Malfunction
Unfortunately I have changed the packs earlier so I don't know which pack is the faulty one. I've cleared the codes and I'll be going for a drive tomorrow and trying to get it to misfire (lol) hopefully then I can check the codes and find the right pack.
Hopefully the other codes dont come back or aren't actually adding to the problem.
Thanks

[sambb]

yep go for a drive and see if you can get another misfire code. If its on cyl 3, switch that coil with cyl 1, clear codes and repeat. If the misfire moves to cyl 1 then you've found your bad coil.

[Snail Style]

Best to move your plug to a different cylinder too, that way you can identify exactly which component it is/isn't. That lambda probe fault might be worth looking into after sorting the misfire too.

[xerxes]

G'day guys,
Sorry to bump my old thread.

A couple days ago my car started misfiring badly again, no power, bad idle.
I got sick of it and finally replaced the 3rd coil pack (as it says in the obd tool).
Cost me $107 bucks. I installed it and the car ran better (more power, better idle)
Thought I had fixed it and I was happy.

Yesterday I pulled into the drive through at maccas and the same thing started happening.
I scanned the car again and the misfire code is still there.
There is also P1116 (Oxygen sensor heating bank 1 sensor : open circuit)
and P1196 (O2S heater Circuit Bank 1 sensor 1 electrical malfunction)

I've pulled the sensor out and cleaned it, still nothing, does anyone know how to test these ones?
Would rather not spend 200 bucks on a new sensor...

Not sure if I'm just tripping but I think it happens more often when the A/C is on and I'm going up a hill.
At my wits end here, any help is appreciated.

[xerxes]

Anyone?
i'm also getting a P0140 - HO2S12 Sensor Circuit No Activity Detected