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Misfire on cylinder 3. Running out of options, any suggestions?
2013 A6 3.0T (USA) with ~140K miles. The catalytic converter on bank 1 is faulty, P0420. (same side as Cylinder 3)
The vehicle consistently throw a DTC for Misfire on Cylinder 3, ONLY after ~5500 RPM. It goes into limp mode - EPC light on. Restarting it twice resets it and it drives well until hitting that RPM ceiling again.
I changed the spark plug to a brand new Audi NGK and swapped coil plugs; also tried a brand new coil plug. Exact same behavior.
Unfortunately I am on a tight budget and I have to get my hands dirty as much as possible to reduce cost. I would appreciate any suggestions of what else to try.
Some ideas:
- Can a clogged catalytic converter cause this?
- Can it be an injector, despite no related DTCs?
- The Audi indie shop mentioned a EGR / PCV issue that may cause this?
you may have a clogged injector, I took mine for cleaning and one was not that great during initial testing. Try running SeaFoam in your gas tank, 1 can per tank - at you own risk! That may help, i've done it before and it worked. I also have clogged catalytic converter on bank 1 but rarely i find a code for low fuel pressure in bank 1, so that could be playing a part with a back pressure or something. Another thought, and that's just a thought, maybe your intake valves are super clogged and fuel/air mixture is off causing misfires. Mine were really dirty
BOPOH could be onto something with the valve coking thing if its not something else. Search the forum as there is a good thread on this topic. Good luck!
Thanks BOP and Dan. I will keep you guys up to date.
A bit of back story that may be pertinent. This all started 1-2 weeks after I went Seafoam and CRC GDI cleaner crazy. I ran about 5 Seafoam cans and 4-5 CRC GDI cleaners through the vacuum line over the course of 2-3 days.
The car started running very poorly as if a block or restriction (cat?) I then ran 3 Cataclean which seemed to bring it back to normal, excluding this problem.
Thanks BOP and Dan. I will keep you guys up to date.
A bit of back story that may be pertinent. This all started 1-2 weeks after I went Seafoam and CRC GDI cleaner crazy. I ran about 5 Seafoam cans and 4-5 CRC GDI cleaners through the vacuum line over the course of 2-3 days.
The car started running very poorly as if a block or restriction (cat?) I then ran 3 Cataclean which seemed to bring it back to normal, excluding this problem.
well that could be the reason, as you dislodge big amount of solids they may get stuck at the catalytic converters. Also there is an issue with crankcase pressure regulator valve, i believe it cause excessive oil consumption through piston rings, eventually clogging cats. All in all i think your cats are causing your issue, i'm in the same boat lol I think i'm gonna take them off and drink a hole just to see if it works before i spend over $400 per catalytic converter
I have experienced the same issue and it was caused by a bad injector. if you want to confirm just swap injectors between two cylinders and if the misfire moves you will know that is the faulty part.
I have experienced the same issue and it was caused by a bad injector. if you want to confirm just swap injectors between two cylinders and if the misfire moves you will know that is the faulty part.
07-17-2018, 09:21 AM
Misfire on cylinder 3. Running out of options, any suggestions?
