Intermittent CEL - 2002 A6q V6

[Cody Forbes]

That G71/F96 would be the path I would travel up. Data log the measuring block that shows that sensors output and look for anomalies. At cruise it should be reading under 1000mbar (actual value depends on load, throttle position, etc.). Under acceleration it should measure within ~50mbar of 1000. Engine not running should be very near 1000mbar depending on your altitude.

-Cody Forbes (mobile)

On Aug 19, 2013, at 10:15 AM, ZZracing at aol.com wrote:

> I have monitored this list for may years, rarely contributing (you guys 
> know more that I, and I usually find answers in archives).  Car is 2002 A6q 
> Avant V6 3.0, 92,000 miles.  I am totally stumped by intermittent drive 
> problem: car will suddenly feel as if it has not gas (no response to gas pedal), 
> then suddenly resume or do heavy acceleration (like too much pedal).  When 
> this occurs, it will generally show the ESP light first, and, a bit later, the 
> CEL.  As long as ESP and CEL show, the car will drive well.  Sometimes, the 
> ESP light will clear, after which the car will throw a hard downshift when 
> coming to a stop.  If I clear the codes, problem returns within 4 or 5 miles.
> I have replaced fuel pump and fuel pressure valve, and a few vacuum lines 
> which looked a bit dodgy, with no improvement.
> VAG Com shows:
> 16485 - Mass Air Flow Sensor (G70)
>             P0101 - 008 - Implausible Signal - MIL ON 
> 16685 - Cylinder 1
>             P0301 - 008 - Misfire Detected 
> 16688 - Cylinder 4
>             P0304 - 008 - Misfire Detected 
> 16891 - Idle Control System RPM
>             P0507 - 001 - Higher than Expected. - Intermittent 
> 16490 - Manifold / Barometric Pressure Sensor (G71) / (F96)
>             P0106 - 008 - Implausible Signal 
> 17550 - Load Calculation Cross Check
>             P1142 - 002 - Lower Limit Exceeded - Intermittent 
> Readiness: 0000 1100
> 
> Any ideas?  Thanks in advance.
> 
> Dave Zube
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