I have a 2000 Audi A6 2.7T six speed manual. I replaced all six spark plugs. It worked great for 3 days. Then it started to misfire and the engine light came on. I got the error code P0305 “Cylinder 5 misfire.”

I disconnected coil 5 and it had no change in the rough idle. This verifies I have the correct cylinder (middle driver’s side).

I bought a new ignition coil and installed it – no change. I put the old spark plug back in – no change. I put the old coil back on with the old spark plug – no change. I then put the new spark plug back in.

I disconnected coil 5 and hooked up the new coil pack with an old spark plug. I started the car up and touched the plug to the engine block. It did not appear or sound like it was sparking (even in pitch dark).

I have tried to see if there were any loose connections or degraded areas in the wiring harness. I found nothing.

I also know the cylinder is getting fuel because I can smell the unburned gas in the exhaust. It also smelled like rotten eggs when I first felt the misfire and drove it about one mile to the house.

I don’t want to purchase any other expensive and / or time consuming parts or tow it to the Audi dealer that is 80 miles away and pay for $85 / hour labor…..unless it is necessary. I know it may be the ignition control unit (~ $150).

Is there anything else I can do to narrow down my problem or is the ignition control unit the next best option?????

If it is my next best option, where are the two ignition control units located? I don’t see anything that looks like the pictures of an ICU located in the wiring between the coil packs and the black plastic box in front of the driver’s side of the windshield. Is the ICU in the box?

 

ICU/ICM under the panel over the air box area on the pass side. Swap them. See if your trouble switches to the other cylinder.

Email joe@axis or ---->

http://www.purems.com/products/product.php/II=1957

 

Oh, if you want a cheeeep alternative, i have installed these and they worked fine FWIW:

http://cgi.ebay.com/ebaymotors/AUDI-...ht_2418wt_1185

Seemed just fine, and I have had great luck with the seller.

 

Thanks for the info. I swapped the units and the misfire switched to cylinder number 2. Ordering the part off ebay like you recommended. Thanks again.

 

You're very welcome.

 

I replaced the ignition control unit. The engine runs fine. When I erased the old codes and ran the car again, it had three new codes. These codes are not in the book. P1364, P1367 and P1370. I had my computer reprogrammed with APR software three years ago. Does this have anything to do with it?

Thanks

 

I found the codes on the following sight:

http://www.obd-codes.com/trouble_codes/audi/

P1364 Cyl. 4 ignition circuit Open Circuit

P1367 Cyl. 5 ignition circuit Open Circuit

P1370 Cyl. 6 ignition circuit Open Circuit

open circuits don't make sense since the car is running fine? What should I do next? I am still wondering if it has something to do with the APR programming? Is it safe to drive without damaging the car?

 

Threads like this is what gives undeniable value to Audiworld. Audiworld and VAG-COM is why I keep buying Audi vehicles. BTW, cylinder 5 is linked to Ignition Amplifier Module closest to the radiator with brown harness connectors and cylinder #2 is the ICM closest to the firewall with black harness connectors. Thanks guys. Good to be boosting on all pots.

 

This is great info. I'm chasing a misfire, can you tell me which ICM's service which coils/cylinders please?

K9