Rough Idle / Mis Fire Bank 2 / Smooth under higher Rev and no Mis Fire (Car holds many memories)

[StuartIrons]

Good Morning All,

Firstly thank you for letting me join, the Audi means a lot to me as it was once owned by a very close friend and the issues are making it impossible to use let alone keep.

The issue started with rough running which seems to be due to PCV valve this was replaced along with new spark plugs and coil packs and it was sort of ok not perfect but much better.

Then a bolt from the bank 2 CAM came loose and stripped a segment from the variable valve timing casing causing the solenoid to leak, months of searching I found a replacement and took the task to replace the casing including all seals and bolts and the timing belt.

I made sure the cams were correctly locked in place using the manufacturers tool and replaced all component for new and double checked the timing marks and made sure roller was correctly aligned, spent hours reading the manual and double checking.

The car started no issues and was smooth and then the rough idle started only bank 2 (passenger side) started throwing up miss fires, we checked the cats a bank 2 was blocked and this improved the running but still rough but very smooth on higher than idle reeves.

Errors in the ECU were missfires on bank 2 and cam sensor issue, bank one is fine no miss fires.

There is a lot of troubleshooting undertaken but I am struggling to get any traction to resolution as I want to keep the car given the memories but it appears to be fighting me.

My first thoughts are timing but it was still an issue before the variable valve solenoid started pump oil out.

In terms of compression I an 950 on cylinders 1->3 and 1350 on cylinder 4->6.

I have run VCDS and struggling to find a convincing method for troubleshooting, the cam sensor issue only came post timing belt change.

Any thoughts would be appreciated.

Audi A4 3.0i v6 Quattro (2001) B6

Edited September 28, 2022 by StuartIrons

[Steve Q]

Definitely could be mis alined cams. But worth replacing the cam sensors might also be worth getting it to a garage for more diagnostics. Also what condition is the battery? A failing battery can flag up odd fault codes due to not providing enough power to electrical systems. 

[StuartIrons]

Thank you Steve Q

The car has brand new battery.

I will move to replace the cam shaft sensor, just unsure how the alignment could be out as everything was locked in place before the belt was removed.

Edited October 3, 2022 by StuartIrons

[Steve Q]

11 hours ago, StuartIrons said:

Thank you Steve Q

The car has brand new battery.

I will move to replace the cam shaft sensor, just unsure how the alignment could be out as everything was locked in place before the belt was removed.

Good point. I'd definitely look at the sensor then. Or sensor wiring.