Hi all, having some issues with my 2003 A4 3.0. Took car to Audi for engine light, they found misfires on cylinders 4,5 and 6. All ignition coils replaced, new spark plugs, replaced Coolant Temp sensor, repaired crankcase vacuum hose. Light came back on, replaced Evap purge Valve and then replaced one Catalytic converter (Bank 1) due to it being under threshold. Still showing misfires! Now they want to replace the Engine Control Module, but aren't sure this will correct the problem. Well over $3000 in repairs already. Any advice? I am feeling like I am being taken for a ride here.

 

I think you are too - for one, an "under threshold" code could just as easily be a faulty secondary O2 sensor ($150 for the part from a dealer). Misfires can result from a bad or dirty MAF or primary O2 sensor as well. I'm also curious whether they found any additional fault codes for anything besides the three cylinders misfiring. Did they give you a list of the codes they pulled? If not, can you take the car to advance auto parts and get the codes pulled? Or do you have VagCom and the cable to do it yourself? It sounds to me like they're just throwing parts at the problem rather than troubleshooting.

 

Thanks for the reply. I forgot to mention that they said the engine is running "as smooth as glass". Forgive me if I don't give the correct info, I have the paperwork showing several codes: po421, po441, po300, po304, po306. This was before replacing anything. PO116 and po118 caused them to replace coolant sensor. They said it is still showing misfires (same original codes) after replacing Cat.

 

So the dealer said it was running "as smooth as glass"? Have they done the ECU update to cure random misfires yet? There is supposed to be a new TSB for the 3.0L engine which cures random misfires the ECU's programming creates, the reflash remaps the ignition and fixes most of them. If that reflash doesn't fix it its VERY bad news on a 3.0L. Typically it could either be camshaft or clyinder failure.

 

They said they couldn't do that because the computer was bad,and would not be able to update the software on a faulty computer? They said the computer is throwing misfire codes when it's not misfiring.

 

In regards to the Cat being the problem, would the cost be $2000? And the cylinder failure?

I have P0421. I also noticed a tiny bit of oil leak at the drivers side cyclinder in the area of the screw (see pic). I'm guessing in your case the engine isn't actually misfiring? In my case, I am getting occasional misfires, rough idles and jumps in RPMs- on some days, usually after a lot of driving. So, I'm hoping that this isn't causing any other damage to the car. And I'm expecting that the seal is bad and oil is getting into the spark plug causing misfires.

 

I have a hard time believing the computer is bad, simply because I work in the defense avionics field and electronics rarely just fail, even in an aircraft which sees far higher stresses and temperature variations than an Audi ever will. I still feel that you're paying hand over fist for them to basically take shots in the dark at your expense by just installing parts that aren't fixing anything. Personally, I wouldn't pay for anything further other than the part that eventually fixes the car and the labor to install that part.

 

What a load, if the computer was bad it wouldn't even communicate. Changing the ECU WILL fix the problem, but you'll end up paying thru the behind to fix it.

 

The stock eberspacher cats cost $1,000 a pop, and installing them isn't easy either.
That oil leak is just a valve cover gasket, nothing major there, you should replace them because it will soak the coils in oil. IF your engine actually is misfiring i would just order a set of new ignition coils (all 6) from www.ecstuning.com The stock push down Bremi coils suck and always misfire. Change those first and don't drive the car until you do, because raw fuel getting in the cats are what destroys them.

 

I contacted Audi of America today who is looking into the situation. Audi dealer claims that the ECU is faulty, and they cannot upload the new software because it will stop when it reaches malfunctions in the computer. It is throwing random misfire codes for cylinder 3, so he is replacing spark plug on that cylinder to test with new computer. They "believe" this is purely electrical, and said they would have known if there were something catastrophic with the engine.