Help with Erratic Idle and VAG Codes
 

So I've had some issues arise with my 06 Audi A4 S-Line in the past few days. All of a sudden, under idle it started to become erratic and fluctuate from 800-1200 rpms randomly. Sometimes, it jumps up to 2000+ rpms then comes back down. Shortly after I noticed this happening, the MIL light turned on. My buddy connected it to his VAG software and ran the codes for me. We also noticed a misfire in one of the cylinders that may or may not be related. I had the dealership do the coil pack recall on my car today but the idling symptoms are still there. Today, I'm going to check on the HPFP cam follower sleeve to make sure that didn't wear out. I'm also going to inspect the PCV valve.

Here are the codes it originally threw. We cleared those and a few more immediately showed up again. I'm copying both print outs. If you have any suggestions on what could be happening I'd greatly appreciate it.

ORIGINAL CODES THAT WERE CLEARED:
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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: WAUEF78E16A044084 Mileage: 142670km/88651miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06F-907-115-AXX.lbl
Part No SW: 8E0 910 115 M HW: 8E0 907 115 D
Component: 2.0l R4/4V TFSI 0070
Revision: --H10--- Serial number:
Coding: 0104010A180F0120
Shop #: WSC 65728 1018 854933
VCID: 2B5EE5EFF377

5 Faults Found:
008801 - Boost Pressure Control Valve (N249): Mechanical Malfunction
P2261 - 008 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 0
Fault Frequency: 93
Mileage: 118369 km
Time Indication: 0

Freeze Frame:
RPM: 2848 /min
Load: 10.2 %
Speed: 106.0 km/h
Temperature: 85.0°C
Temperature: 12.0°C
Absolute Pres.: 1010.0 mbar
Voltage: 13.970 V

001602 - Sensor Reference Voltage A: Circuit: Low
P0642 - 002 - Lower Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 0
Fault Frequency: 4
Mileage: 139568 km
Time Indication: 0

Freeze Frame:
RPM: 0 /min
Load: 0.0 %
Speed: 00 km/h
Temperature: -40.0°C
Temperature: -40.0°C
Absolute Pres.: 0.0 mbar
Voltage: 0.000 V

004506 - Fuel Pressure Sensor (G247): Malfunction
P119A - 001 - Upper Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 142127 km
Time Indication: 0

Freeze Frame:
RPM: 825 /min
Load: 14.5 %
Speed: 0.0 km/h
Temperature: 64.0°C
Temperature: 19.0°C
Absolute Pres.: 990.0 mbar
Voltage: 14.097 V

008583 - Bank 1; System too Lean at Idle
P2187 - 004 - No Signal/Communication - MIL ON
Freeze Frame:
Fault Status: 11100100
Fault Priority: 0
Fault Frequency: 2
Mileage: 142289 km
Time Indication: 0

Freeze Frame:
RPM: 1210 /min
Load: 12.5 %
Speed: 0.0 km/h
Temperature: 84.0°C
Temperature: 24.0°C
Absolute Pres.: 1010.0 mbar
Voltage: 13.716 V

001287 - Idle Control System RPM: Higher than Expected.
P0507 - 001 - Upper Limit Exceeded - Intermittent - MIL ON
Freeze Frame:
Fault Status: 10100001
Fault Priority: 0
Fault Frequency: 6
Mileage: 142417 km
Time Indication: 0

Freeze Frame:
RPM: 1403 /min
Load: 10.6 %
Speed: 0.0 km/h
Temperature: 87.0°C
Temperature: 35.0°C
Absolute Pres.: 990.0 mbar
Voltage: 13.716 V

Readiness: 0000 0000
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CODES THAT SHOWED UP IMMEDIATELY AFTER WE CLEARED THE ABOVE CODES:

================================================== ========
Monday,01,November,2010,18:35:18:40294
VCDS Version: Release 10.6.1 (x64)

Address 01: Engine Labels: 06F-907-115-AXX.lbl
Control Module Part Number: 8E0 910 115 M HW: 8E0 907 115 D
Component and/or Version: 2.0l R4/4V TFSI 0070
Software Coding: 0104010A180F0120
Work Shop Code: WSC 65728 1018 854933
VCID: 2B5EE5EFF377
2 Faults Found:

008825 - Leak in Air Intake System
P2279 - 002 - Lower Limit Exceeded
Freeze Frame:
Fault Status: 01100010
Fault Priority: 0
Fault Frequency: 1
Mileage: 142678 km
Time Indication: 0

Freeze Frame:
RPM: 805 /min
Load: 17.2 %
Speed: 0.0 km/h
Temperature: 78.0°C
Temperature: 52.0°C
Absolute Pres.: 1000.0 mbar
Voltage: 13.208 V

004506 - Fuel Pressure Sensor (G247): Malfunction
P119A - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 142678 km
Time Indication: 0

Freeze Frame:
RPM: 745 /min
Load: 15.3 %
Speed: 0.0 km/h
Temperature: 79.0°C
Temperature: 53.0°C
Absolute Pres.: 1000.0 mbar
Voltage: 13.335 V


Readiness: 0110 0101

I have had the same experience with the idle. Had the codes pulled by autozone. p0177 and p0507 i think. Local repair shop says it is the pcv valve, will know for sure after I drive it a few days. $16 part and a $180 bill later.

The idle air control system, higher than expected fault is usually attached to the intake breather on top of the engine on the valve cover. the way you test it, its bad if you can't take off your oil cap.

related idle issue
 

when I am driving in first gear really slow, around 1500 1800 rpms and I keep my foot steady on the gas the rpms jump 300 to 500 rpms. It is very strange and annoying.