03 A4 - Running Very Rough

[macbeck22]

One morning when I started my car last week I found that it was running very rough. Prior to this it had been running without any issues that I noticed. The check engine light is on but intermittently. I hooked it up to the VAG tool and the results are below. I looked around on the forums and internet but can't find anything that answers all the questions. Any guidance on where to start looking would be greatly appreciated!
Thanks!

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Chassis Type: 8E - Audi A4 B6/B7
Scan: 01 02 03 08 09 0F 11 15 16 17 18 36 37 45 46 55 56 57 65 67
69 75 76 77

VIN: WAULC68E93Axxxxxx Mileage: 123250km/76583miles
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Address 01: Engine Labels: 06B-909-518-AMB.lbl
Part No SW: 8E0 909 518 AF HW: 8E0 909 018 A
Component: 1.8L R4/5VT G 0003
Coding: 0016751
Shop #: WSC 09401 444 84380

9 Faults Found:
17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 001 - Upper Limit Exceeded - MIL ON
17519 - Oxygen (Lambda) Sensor Regulation: Bank 1: System too Lean
P1111 - 002 - Lower Limit Exceeded - MIL ON
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 008 - Implausible Signal - Intermittent - MIL ON
16685 - Cylinder 1: Misfire Detected
P0301 - 008 - Implausible Signal - Intermittent - MIL ON
16687 - Cylinder 3: Misfire Detected
P0303 - 008 - Implausible Signal - Intermittent - MIL ON
16686 - Cylinder 2: Misfire Detected
P0302 - 002 - Lower Limit Exceeded - Intermittent - MIL ON
16688 - Cylinder 4: Misfire Detected
P0304 - 008 - Implausible Signal - Intermittent - MIL ON
17536 - Fuel Trim; Bank 1 (Mult): System too Lean
P1128 - 001 - Upper Limit Exceeded - Intermittent
17658 - Fuel Level too Low
P1250 - 008 - Implausible Signal
Readiness: 0000 0000Chassis Type: 8E - Audi A4 B6/B7
Scan: 01 02 03 08 09 0F 11 15 16 17 18 36 37 45 46 55 56 57 65 67
69 75 76 77

[Philip Swanson]

WOW! there's a lot going on there. I don't have too much experiance with Audi's but it seems to be pointing towards the fuel system. Have you tried checking the fuel filter and pump?

[macbeck22]

I was just playing around with it again tonight. In the VAG tool I can see it is missing on all 4 cylinders pretty consistently at idle. When I unplugged the MAF the rough idle went away and the miss count almost went away all together. Could all this just be caused by a bad MAF?

[raypicano]

here are my codes
p0234 turbocharger overboost condition control limit exceeded
p1111 o2 sensor bank 1 system too lean
p1136 system lean
p0300 random misfire detected any cylinder
p0301 cylinder 1 misfire
p0302 cylinder 2 misfire
p0303 cylinder 3 misfire
p0304 cylinder 4 misfire
p0507 idle control modulerpm higher then expected
please help
thanks

[LT1FirebirdSLP]

I'm willing to bet money your coils are shot. You'll need to replace all 4. Even if all four aren't broken, It's a good idea.

The 4 misfire codes are directly attributed to the coils. The lean condition comes as a result of incomplete combustion aka misfire. The overboost condition is most likely a result of the computer trying to make sense of what is going on with your car.

I would change the coils. Clear the codes. Then drive it for awhile. See if the check engine light comes back on again. If the overboost condition comes back I would start looking at the Turbo Boost Pressure Sensor. Other than that, coils run for about $45 - $60 / ea. It is highly suggested you replace all four to ensure you have an even burn across all four cylinders.

Hope I helped.

[raypicano]

Could it be plugs

[LT1FirebirdSLP]

Could be. I highly doubt. Unless there is some other underlying problem like worn piston rings or a blown head gasket which is allowing oil to seep into the combustion chamber and foul the plugs. I'd be willing to bet money its not the plugs. Plugs should last 100K or more.

[coving21]

Listen to LT1 and change out your coils, all of them.

[raypicano]

But I changed those a couple months ago any other ideas

[LT1FirebirdSLP]

I would change them again. Ill check my service manual to see whatelse I can pull up for misfire.

Now that I am looking at your codes I see the overboost condition and it makes me think more and more.

I don't know how the air/fuel system in the audi is setup to respond to overboost but I am thinking when the computer senses over boost it cuts spark to slow down the engine thus slowing the turbo and lowering the boost PSI. Now our audi's have a diverter valve, that diverts extra gas and fuel back into our intake but keeps the boost below what the factory sets it at (I think 8 psi, or 15psi. its one of those) If the diverter valve is stuck closed the gases cant escape and boost continues to climb above the factory setting. When this happens i think the computer flags it as overboost and cuts spark setting your misfire codes.

If it is not the coils I would look at getting a new DV. Don't overboost too long you could REALLLY break something. $$$$$$

Someone could maybe point him in the right way with DV selection?