A6 misfire

I have a misfire on my Audi A6 2.7t Quattro. It started on Cyl #3 and 4. I put in some fuel injector cleaner and replaced the plugs and Cyl #3 misfire went away. I replaced the coils on Cyl #3 and #4 but it
still misfires. This is a very strange misfire. It misfires at idle, off idle and under load but seems to go away at 2000 rpm with no load and 2800 with load. This all started on the same day. Could it be fuel injectors?
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Is the compression OK? There's a scary chance that the head gasket blew out between the two cylinders.
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wrote:

ok, I'l confess to not knowing this for certain, but given the 2.7t is a V6, does Audi number the banks 1-3 and 4-6, or do they stagger (odds on one side, evens on the other)?
/daytripper '00 s4 6spd
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Standing in front of the car facing the radiator:
passenger side drivers side
3 6
2 5
1 4
/ Radiator /
wrote:

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Excellent.
And that would, as I suspected, rule out a siamesed head gasket on a 2.7t between cylinders 3 and 4...
/daytripper '00 s4 6spd
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Compression is fine
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wrote:

disconnect the battery and let the ecu set back to default..............reconnect and run.
does it do it now.
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wrote:

Disconecting the battery may cause the ECU to loose its memory on the throttle body alignment settings, not a good idea unless you can re calibrate it ;-)
Steve.
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On Sun, 23 Sep 2007 23:30:34 +0100, "Steve68s"

TBU recal after battery disconnect/reconnect: put key in ignition, turn to run position, wait three minutes. No biggie...
/daytripper '00 s4 6spd
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More info: I replaced the injector on cylinder #4. Bought a VAG reader at virtualvillage.com for $139 bucks. Reads OBDII and CAN too. I cleared the codes ran the engine and reread them. I got P1458, P0030 and P0304. Are you sre about the ECU? There is a test on the reader to test the ECU. What about the radio code when I disconnect the battery?
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Who said anything about an ECU?
P0030 is a bogus OBD2 code. Try again. The second digit cannot be 0. P0304 is a generic OBD2 code for cylinder 4 misfire. Got a bad coil pack? P1458 is an Audi-specific OBD2 code for "Exhaust gas temperature sensor 2 short to ground"
/daytripper '00 s4 6spd
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I must have written P0030 down wrong, It was a generic cylinder misfire. I already replaced the coil pack, spark plug (although it might be fouled again) and the injector. Could P1458 cause cylinder misfire?
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I don't know, sorry. I would expect the *bank* for that sensor to exhibit symptoms, not just one of the three cylinders, but I suppose even that could be in doubt. I'd certainly try to resolve that first, however, and see what happens next.
/daytripper '00 s4 6spd
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I switched the ignition modules and all the codes went to the other bank. It's the module nothing else.
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I changed the ignition module. No codes left and car runs great.
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How do you know you have a misfire? You need to get the codes pulled. Go to Autozone, they can do it for free. Then you can find out via Google exactly what the issue is.
Dan D '04 A4 1.8Tq MT-6 Central NJ USA
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My neighbor has an ODB2 code reader. It says misfire on cylinder #4. I can't get more specific without a VAG reader.
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