r171amg

I looked over many different discussion on several forums that covered lots of ground. But the issue I'm having is taking a twisted turn that I need help with... This total story stretches almost 3 weeks, care driven with CEL on for a total of 15 miles..

Before having a scanner: My 05 B6 S4 automatic displayed a flashing CEL (then turned solid) two days after I added a Chevron Techron Concentrate Fuel System Cleaner (20 oz.) before completely filling up the tank with premium gas (related to CEL? not sure). I replaced all 8 coil packs (Audi OEM updated Packs) and 8 plugs (Bosch Platinum 4). The CEL went away by itself in one day after about 4 warm-ups/cool-downs. Then it came back on flashing then solid the next day. I parked the car for 5 days so it wouldn't get worse...

Dealer Visit: Then took the car to the dealer. They checked everything, from the vacuum lines, to all of the connections, and that they think it is the spark plugs. This is exactly what the diagnosis said "82847 INCORRECT SPARK PLUGS CAUSING MALFUNCTION INCORRECT SPARK PLUGS CAUSING MISFIRES. RECOMMENDED 8 NEW SPARK PLUGS." cost $360 ($124 for parts LOL).... They gave me the following codes p0300 p0305 p0306 p0307. Basically a random misfire for the p0300, while the rest are misfires on cyl 5, 6, and 7. I declined the repairs and told them that I previously told you guys that the car had a CEL on, I changed the plugs and coil packs, can't you look at something else. They said that we have to change the plugs and go from there (they just couldn't think outside of the box for a second)....I said screw this, I picked up the car (wasted $153), with a flashing CEL and took it home.

Scanner in hand: I confirmed the dealers codes Today. After clearing the following codes:
* Random/Multiple Cylinder Misfire: P0300
* Cylinder 7 Misfire Detected: P0307, Value of resistance too small
* Cylinder 5 Misfire Detected: P0305
* Cylinder 6 Misfire Detected: P0306

I turned on the car, and CEL flashed then turned solid with the following codes CEL:
* Random/Multiple Cylinder Misfire: P0300
* Cylinder 6 Misfire Detected: P0306

Thanks to JHMotorsports that spent over an hour with me on the phone last night, answering my questions and giving me advice

I switched injectors #5 to #1 and injector #6 to #2 and cleared the codes. Turned on the car and got the same codes again and CEL (car on idle, not driven):
* Random/Multiple Cylinder Misfire: P0300
* Cylinder 6 Misfire Detected: P0306

Switched coil pack cylinder 6 with cylinder 5 coil pack. Same two codes and CEL (car on idle, not driven):
* Random/Multiple Cylinder Misfire: P0300
* Cylinder 6 Misfire Detected: P0306

Changed coil pack cylinder 6 with a coil pack i had sitting around (i had changed all coil packs a week earlier).
Same two codes and CEL (car on idle, not driven):
* Random/Multiple Cylinder Misfire: P0300
* Cylinder 6 Misfire Detected: P0306

Put a new cheap single electrode spark plug in cylinder 6. Same two codes and CEL (car on idle, not driven):
* Random/Multiple Cylinder Misfire: P0300
* Cylinder 6 Misfire Detected: P0306

Went back to last weeks setup with the 8 new coil packs and the 8 new Bosch platinum 4 plugs. Checked for vacuum leaks, no leaks...

Drove the car to Autozone and checked the battery and alternator and they both sounded good.
At this point the car started shaking insanely on idle, and the engine was misfiring so bad that it sounded almost like someone playing on a drum. No problem under open throttle, but the car feels weak.
At this point the car had around 10 miles to go on the fuel tank ( I wanted it to empty so I can refill it with fresh fuel). I checked the codes again I got the following (got the same codes at 0 miles to empty):
* Cylinder 6 Misfire Detected: P0306
* Cylinder 5 Misfire Detected: P0305
* Cylinder 7 Misfire Detected: P0307
* Cylinder 1 Misfire Detected: P0301

With an almost empty tank. I filled up the tank with fuel, cleared the codes and drove 2 miles home and got the following codes:
* Cylinder 6 Misfire Detected: P0306
* Cylinder 5 Misfire Detected: P0305
* Cylinder 7 Misfire Detected: P0307
* Cylinder 1 Misfire Detected: P0301
* Cylinder 2 Misfire Detected: P0302

I will be checking the compression of all cylinder tomorrow. I will also clean the MAF and trouble shoot it.

I need help, advice, comments... I don't I'm running out of options before having to dish out some serious cash just to get this S4 running...

RVTS4

I would do this....it seems like you have good cylinders for 3 and 8. Swap those two (coilpacks and plugs), with two previous known bad ones (7 and 1). Then turn it on and see if you still get the codes on the known bad ones (7 and 1), if so, then the coilpack and the sparkplug that you switched out are actually good. That would have me think its a bad sensor. Using the techron cleaner remove junk, but it goes to the cats.....YOu could do this for all the bad ones to cycle through them, wit the two known good ones (3 and 8). I'm a test engineer, I do stuff like this all the time to debug faults and problems on radar and comm systems.

zigzag1

Timing Chain Tensioners. Sorry to say it but my experience with similar symptoms revealed it to be the tensioners. My car 04 S4.

2005AUDIS4

This is kind of a tough one as many things can cause these codes; and you begin to feel as if we're just pulling straws. Check the gaskets to make sure that you have a good seal on all major engine parts (exhaust, intake etc...)

Next, I recommend taking it to a good mechanic (not the dealer) to have it repaired. Get a recommendation from someone. Should save you some serious cash.

Doug Funny

I'm having almost the exact same issue with my C5 Audi S6. Pretty much done and troubleshooted everything you've mentioned except smoked the vacuum lines. But in my case, only cylinders that ever give me a problem are 7 & 8.

Basically also the same exact problem this guy is having:

http://audiforum.us/c5-platform/1058...m-misfire.html

y2gplaya69

I agree with zigzag1, I have experienced similar symptoms and the dealership actually took the engine apart for diganoise and found a piece of the timing chain tensioner broken away thus causing the timing chain to "flap".

S62001

Hi guys, I have a 2001 S6 and am having exactly the same problems as in this thread - same codes... Finally resolved a bad O2 sensor, changed both the fronts out, and now am getting:

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16692 - Cylinder 8: Misfire Detected
P0308 - 35-10 - - - Intermittent
16691 - Cylinder 7: Misfire Detected

with flashing CEL..

Car idles like a bag of bones, whole thing shakes. Horrible. Am thinking now that the O2 sensors are working fine they can read these other faults, does this make sense?

Also am getting horrendous drumming/vibes in the car from 50mph upwards - have rebalanced, repressured and retracked all 4 wheels, but doesnt make any diff.. So am thinking either something horrible is wrong with the car (driveshaft/bearings), or the car has been sat idle (previous owner barely drove it) so long on its crappy Nexen tyres that the tyre or alloy is out of shape.. Either way its not looking good..££££

Any advice you guys could throw would be much appreciated!

Please post up when you know how you make some progress, as will I ! Good luck to all!

Pete@ECSTuning

There are two service bulletins on an engine misfire.

The first one is 240872. It states that the intake manifold bolts can come loose causing an engine misfire when hot. The fix would be to tighten the bolts and if it doesn't help then to replace the intake manifold gaskets.

The second service bulletin is 240850. It states that the ECM needs reprogramming because of the improper operation of the Intake Camshaft Adjuster Valves.

Might be something to look into if all else fails.

Pete

s4master1

sadly nobody has actually log any actual values/readings from the engine while running, C'mon the engine is actually misfiring, how hard can it be?
you can check timing with a vag as well most sensors (inputs) and actuators (outputs).
we have the obvious (plugs, coils, leaks) out of the way.
now let's check deeper, voltage reading to the injector before and after resetting the faults (ecm may at times shut the circuit off when no ignition present)
collapsed hydraulic lifter? rare but seen it couple times.
but mostly when at the dealer tell them not to assign your car to a Jr mechanic.

Militant-Grunt

I have a suggestion that you may want to try. Run a compression test on the cylinders that are throwing the misfire codes, figure out what your compression is. If that comes back positive, there are other potential issues with that V8 that can cause misfires.

The intake manifold for instance has butterfly valves, they are known to collapse at higher mileages and cause poor running and misfires. May want to take a look in there to see if they are all intact. Ive seen one fail in such a way that a piece ended up in the valve channel and caused head damage. (going back to compression test...)

Also on occasion a MAF will cause misfires as well. If all these come back good, Id take a look at those cam chain tensioners.