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View Full Version : Need Help Diagnosing Issues with My Wife's 2006 Audi A4 B7 2.0L



Quattro_Junkie
10-19-2024, 09:54 PM
Hello, Audi community! I’m reaching out for your expertise as I navigate some issues with my wife’s beloved 2006 Audi A4 B7 2.0L with an automatic transmission. She is the second owner and purchased it in 2015 with about 70K miles, and it currently sits at 147K. We've done our best to maintain it, including immediately replacing the water pump ourselves the week we purchased it and changing the oil every 3-5K miles. However, since moving to a new home without a garage, I’ve had to rely on a mechanic recommended by a friend who specializes in Audis for some recent repairs.

Symptoms:
No boost (we really miss that!)
Clicking noise at the top of the engine near the back
Jerking when shifting into second gear, particularly in traffic at lower speeds, especially on downhill slopes around 3K RPM
Check engine light is on with codes: P0442, P0456, and P0299


The following repairs were completed by my mechanic over the past year:
Coolant Hose Flange Replacement Kit
Valve Cover Gasket (due to oil leak)
PCV Valve Assembly
Thermostat (seal leaking)
Vacuum Pump (leaking)
High Pressure Fuel Pump (I installed this; had to replace the cam follower shortly after, possibly due to inadequate lubrication)
High Pressure Fuel Sensor (replaced due to rough idling and potential clicking noise)

I have a few ideas on what might be going on:

Mass Air Flow (MAF) Sensor: Thinking of cleaning or replacing it. If cleaning doesn't help, I might go for a locally available option like a Blue Streak Electronics MAF Sensor or an OEM if in stock.
Fuel Filter: Considering replacing it as a precaution.
Gas Cap: Might need to replace it for the small leak indicated by the P0442 and P0456 codes.


I plan to start with the MAF sensor, but I’d love to hear any insights or suggestions from you all. What else could be causing these issues? My wife is ready to get a new car, but with a kid on the way, I’d like to keep her A4 running for as long as possible.

Thank you in advance for your support and suggestions!

a4audi4fun
10-20-2024, 09:40 AM
147K mi - might be time for a carbon clean if that hasn't already been done; poor throttle response is a symptom of that.

Older_not_Wiser
10-24-2024, 09:44 AM
P0299 could be diverter valve diaphragm split, or other boost leak. Maybe N75, but usually if the N75 starts failing, you lose boost, but do not usually get P0299.

Other codes could be N80, gas cap or other leak in evap system. Can be hard to trace.

Not sure MAF and fuel filter are causal for these codes. DV, N75, N80 and gas cap are not terribly expensive to buy and replace as parts darts so maybe worth it. DV and N75 are a bit of a pain and best dealt with in service position so it might cost a bit to have someone do it, but not horrible.