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Matt, Mechanical Engineer
Category: Audi
Satisfied Customers: 22893
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have an '03 A4 avant with erratic acceleration in 1st and

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Hi I have an '03 A4 avant with erratic acceleration in 1st and 2nd gear. And I seem to have some oil being sprayed out around fuel rail under engine cover. Also seems to be a hissing coming from somewhere around throttle body but I can't locate its exact position because the noise of the engine idling is too loud. Idle is smooth its just under acceleration. I have noticed a bit of oil by top of dipstick holder too.


this sounds like the vacuum hose that runs back to the cam cover and is attached to the cover with a PCV ( pressure control valve) the valve is there to only allow gas out of the engine and not back in and over time the valve can stick open or otherwise fail or the hose may have sprung a leak - this would explain the oil leak and the erratic idle as air is pulled into the engine that hasn't been metered by the MAF sensor

The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane around each joint in turn. If the engine rev's up you've found your leak.

Now you might think that spraying lighter gas around a hot engine isn’t wise, however the flash /ignition point of gas is about 400°C so you need a naked flame or spark to set it off and I’ve used this method for many years without incident.

Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements

Customer: replied 1 year ago.
Hi thanks I had suspected it was that I will try that test, I have searched on etka for the PCV and I can't find any part named PCV, could you give me a part number or perhaps suggest another name by which it could be labeled. I also have an error code that's saying camshaft adjustment bank ,1 malfunction. But this error has always been there and engine wasn't rough until the hissing started. Where is the part located that this error refers to? I'm assuming it's the n75 or n112 solenoid but can't locate it anywhere.
Customer: replied 1 year ago.
I went through every part for my engine code on the vacuum line section on etka
Customer: replied 1 year ago.
Would it be 32a in this diagram?


part 32a looks like the high load breather valve so yes it could the issue

and part 35 looks like the PCV part to me as it should connect to the cam cover

and the cam adjustment is referring to the VVT ( variable valve timing) function

as the cam pulley will move around to boost power and improve drivabilty

this is controlled by the cam position sensor on the cam cover

but could also be a faulty conrol solenoid or a faulty pulley

if you can tell me the exact code I'll try to help further

Customer: replied 1 year ago.
I have replaced the CPS as it's a cheap part and simple job but still getting the error. 17927 is the code. Had no warning light for this and it has always been there as long as I've owned the car (3 years) by would like to clear the error once and for all. Thanks
Customer: replied 1 year ago.
The rough acceleration is a new problem and the engine warning light is on now constantly.
Customer: replied 1 year ago.
Part 35 is just listed as "solenoid valve" ? A solenoid requires power though doesn't it? And I'm assuming the PCV is a plastic connector type thing?


OK I'd try the vacuum leak test I mentioned earlier

if you remove the oil filler cap with the engine running and the idle speed increase then this is another sign that the breather system is open to the intake and give some direction

regarding the 17927 code this is often an electrical issue and I'd say to 1st clean the connections to the cam position sensor and the VVT actuation solenoid

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