I have an 2006 audi a4 2.0t q. Lately I have a misfiring issue the fault code is p0301 which is misfiring on cylinder 1. I have tried switching coil packs and spark plugs yet the same code still still appeared after resetting. Here is the symptoms= the car run idle fine, while driving fine during engine warm-up. Once the car is warmed up, about 2,600 - 3,400 rpm the engine started to shake and the CEL flashed and sometime stayed on. the misfire seem to happened during acceleration. I did the BSH fix stage one because of a PVC leak. I did tried the taking off my MAF because I read some where here that it may cause a misfire. When I took off the MAF plug the engine shakes a little bit and idle normal... so I think the MAF is not at fault here. While driving it with the MAF unplug the car run fine but once accelerate the car hesitate/ stumble to get up to speed. I'm running out of idea here... =( any tips or suggestion would most be useful. thank you

 

What does the spark plug look like? How many miles on the engine and spark plugs? I would replace the coil pack and the spark plug. After that the only other concern would be the fuel injector.

 

Considering he said swapping coils and plugs makes no difference i wouldn't bother with trying to replace any of them.

Injectors aren't usually a problem on the 2.0, But that would be my starting point.

I would check on the price for one, cause removing the manifold just to swap then reinstall to see if it moves is quite a bit of labor.

Also, if your using a cheap code reader.... And not a VAG-COM or Audi scan tool. It doesn't always show every fault that was recorded but the ECM. I know this for a fact, cause i actually have 100.00 code reader. A little better than your basic one and i have seen the Audi scanner pull more codes than what showed up on mine.

Cause another thing that concerns me is in the case of a faulty injector you usually get some fuel trim faults.

 

Is it possible that it could be carbon buildup. There have been reports with other Audi engines that carbon buildup in the cylinder can cause misfires.

 

I have replaced all the old sparks plug. I even order the latest version of the coil pack yet it. it still misfiring... the car is about 73k as of right now. Im hoping its not the fuel injector...

 

how do i know if i have carbon buildup and how to get rid of it?

 

I order a veg com k+can from ebay. I hope that the right one. about the injector... I hope that not the problem because it look like a bitch to remove the damn thing. you would know how to remove it would you?

 

You could also try the plug wires.

It's possible that one of your wires is broken engine vibrations, and the connected plug in question isn't working as a result.

That's what I would check, being that you've already tried the plugs and the coil packs.

 

You could have a boost leak. Boost comes into play under load and that sounds like your problem. Check that you installed the BSH properly and it is seated and no hoses left unconnected. Check your Diverter valve as well. My money is on a leak.

 

i really hope its a boost leak too....how often does the upgraded 06H145710D DV fail because it is installed on the car before i owned the car?