2002 A6 3.0 with serious misfire following lucas fuel injector treatment

[BiturboContent]

I have spent hours searching and trying to diagnosing this.

Just bought a 2002 A6, 176k. The previous owner says it was running strong until he used Lucas fuel injector cleaner with a fill up 3 days ago. Now it runs horribly, barely idles, has barely enough power to drive, stumbles throughout the entire power band. On the drivers side cylinder bank (bank 2, correct me if I'm wrong) the exhaust manifold was red hot after a five minute drive.

I need to drive it home by Monday, any help would be greatly appreciated. Tomorrow I'm changing spark plugs to NGK copper. I have been working on cars for years so ask me any question. Happy new year fellow enthusiast!


DTCs:

Camshaft position sensor (G40) implausible signal short to another valve.

Load calculation cross check, lower limit exceeded.

Cylinder 3, ignition circuit open

Random, multiple cylinder misfire

Both banks have catalytic converter below the threshold.

[jcjohnson33]

Maybe the injector cleaning dislodged some sediment that is now blocking the fuel rail on the effected side causing a very lean air/fuel ratio. Which will cause the exhaust manifold to run extremely hot & turn red. I thought bank 2 was passenger side, but not totally positive. You could try pulling the fuel lines to see if you are getting equal pressure to each side of the fuel rail.


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[BiturboContent]

Update:

Problem largely fixed! Replaced two coils, (the two that broke when I took them out) and 6 spark plugs with NGK BKR6E.

The cam position sensor code is still there as well as a random cylinder misfire. The car has good power and runs good. Now its time to clean it up!

Thank you for the help jcjohnson33!

[BiturboContent]

Update 2:

The car is running smooth unless you try to go WOT. It then hesitates and the engine light flashes with all cylinders misfiring. I gapped the NGK BKR6E to .44. Does anything think that was too much? Perhaps I should have gone with .30? I don't know what else could be causing this misfire? Bad catalytic converter's? Does this engine have an ignition control module?

[V1nny]

Maybe the injector cleaning dislodged some sediment that is now blocking the fuel rail on the effected side causing a very lean air/fuel ratio. Which will cause the exhaust manifold to run extremely hot & turn red. I thought bank 2 was passenger side, but not totally positive. You could try pulling the fuel lines to see if you are getting equal pressure to each side of the fuel rail.


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very likely. Remove Fuel pressure regulator, and clean it, and its housing. At the same time (without staring the car) replace fuel filter. Drive for a day or so. If filter and FPR cleaning not enough, remove and clean injectors.

[BiturboContent]

Problem keeps returning over time. Cleaned the FPR, changed fuel filter and all 6 spark plugs. Could the camshaft position sensor possibly be a culprit since its reading implausible signal? The valves are loud in the morning but I've read this is perfectly normal on the 3.0 Its also very cold lately, freezing temperatures every day.

How about a coolant or air temperature sensor such as on the MAF? The temperature display on the dash reads 15 degrees colder than it is outside. I'm running out of ideas since the problem is so elusive. Your guys have helped a lot already and I thank you again for that.