Hi all, I've recently purchased an Audi A3 2.0TFSI and have noticed a missfire issue only at idle.

Reading the codes i had a carbon canister fault "reverse flow". checked this and carbon canister working properly so cleared this code. Today i also changed the Purge valve incase this was causing the problem but cylinder 3 is still missing.

What ive done so far:
- New NGK spark plugs
- New ignition coil for cylinder 3
- New hengst fuel filter
- Running fuel additives (wynns xtreme petrol )
- New purge valve.
- Checked the pcv valve gasket & hoses but no issue found.
- Sprayed round intake manifold etc with ether to try and identify any air leaks but none found.

Any suggestions would be helpful. I'm sure it can't be head gasket as under load the engine runs very sweet.

Im thinking about changing injectors next.

Thanks in advance.