A3 3.2 Misfire when Warm

[daniel1920]

Hello, looking for some help for a misfire I have, When the engine is cold its running smooth with no misfire. Once its heated up a bit (about 5 or 10 minutes) it will start to misfire from idle to ~2500rpm. CEL is lit.
I have ran the fault codes and have:
--Misfire on cylinder 3 & 4
--Lamda sensor B2; S1 signal too high
--Linear lambda sensor B2 S1 pump current
--Bank 2 system too rich off idle.
Last night I cleaned the MAF and reset the ECU by disconnecting the battery, ran smooth as a whistle with the CEL off for about 10 minutes until the misfire started again.
Soooo, Any ideas which can help me out will be appreciated, garage is the last resort!

This is posted in VW Audi area, but guess its not specific to VAG

[scjgreen]

Coilpack?

[daniel1920]

scjgreen said:

Coilpack?

I did think this, is it possible when it only happens when warm, and seems to be RPM dependant?

[paoloh]

daniel1920 said:

scjgreen said:

Coilpack?

I did think this, is it possible when it only happens when warm, and seems to be RPM dependant?

Coil pack IMO

[daniel1920]

paoloh said:

Coil pack IMO

Right looks like a good place to investigate after 2 people, hopefully I can pick some up tonight

[SebastienClement]

Had same issues and symptoms with various used cars. Was a coilpack or HT leads every time.

[Dave Hedgehog]

scjgreen said:

Coilpack?

they suffer with coilpack problems, even the R32 golf does

[daniel1920]

Thanks for the responses, what do you all reckon, get 6 and do them all? Or just get 2 and do cylinders 3 & 4?

[Basil Hume]

Do them all.

[pti]

Dave Hedgehog said:

scjgreen said:

Coilpack?

they suffer with coilpack problems, even the R32 golf does

My TT had the same issue.

[anarki]

Yep change the coils. I had the same issue on my 1.8T BAM engine.

[ManFromDelmonte]

It might be cheaper to try spark-plugs before coil-packs. I've resolved similar problems on 2 cars with a change of plugs.

What's the mileage?

[duffy78]

VAG did a recall on coil packs. Might be worth checking to see if yours have been done.

You never know you might get lucky and get offered the recall

[daniel1920]

ManFromDelmonte said:

It might be cheaper to try spark-plugs before coil-packs. I've resolved similar problems on 2 cars with a change of plugs.

What's the mileage?

Around 54k I was thinking just giving them all a switch around tonight to see what effect it has. Will try switching the coils first as its quicker, see if difference cylinders misfire, then do the same with the sparks. Should track down whats playing up

[Vee]

How old is the car ? Earlier VAG V6s had a coil pack rather that individual coils for each plug.
This ends up with lots of hairline cracks with age that affect performance.
The fix is to remove, clean and coat the pack in resin.

[daniel1920]

Its a 2005 with idividual coils. Just had a massive optimistic moment as I realised there was a coil pack service campaign for all petrol VAG engines, but the last owner already had it done, for fks sake, thought I had a set of 6 for free!

[ShaunTheSheep]

You could swap the coil packs that are flagging as dud to another cylinder. If the misfire follows then your wallet will be lighter by the end of the week

With the info given it could still be at least:

• Spark plug
• Coil wiring harness
• Injector
• Injector wiring harness
• Exhaust blockage
• EDIT: Temp sensor

Given it's a VAG, it's going to be the coil pack i know that but still... diagnosing is the fun part!

Edited by ShaunTheSheep on Thursday 17th July 15:08

[daniel1920]

ShaunTheSheep said:

You could swap the coil packs that are flagging as dud to another cylinder. If the misfire follows then your wallet will be lighter by the end of the week

With the info given it could still be at least:

• Spark plug
• Coil wiring harness
• Injector
• Injector wiring harness
• Exhaust blockage
• EDIT: Temp sensor

Given it's a VAG, it's going to be the coil pack i know that but still... diagnosing is the fun part!

Edited by ShaunTheSheep on Thursday 17th July 15:08

Would you recomene just buying 2 coil packs and replacing, or doing some more diagnosis first? Can pick them up for £21 each

[Emeye]

I had a misfire problem with my 1.8T TT that I thought would be coil packs, but it ended up being the wiring to the coil packs that was split, so I guess at higher revs it was arcing over.

Def swap the coil packs around first, save you a heap of cash if it is something else.

Just trace the wiring back - on the TT they were thin wires, wrapping up in plenty of insulation tape solved the problem - a new loom is very expensive and tricky!

Good luck.

[daniel1920]

Right I've just changed coil packs 3 & 4, should the symptoms go straight away after changing the packs? Because they havent!!