Ok, so the check engine light is burning brightly on the dashboard of my 2000 A6 2.7t. The codes that it is throwing are 1136 and 1138 which according to the Bentley manual are for the left and right bank running too lean (air and fuel mixture is not correct or out of spec). From research I have done this can either be cause by the MAF reading incorrectly or a vacuum leak on the engine.

Can anyone confirm if this is true and if so I am going to do the cheap things first and replace the vacuum hose first before replacing the MAF unit.

Does anyone know what size vacuum hose I need for the 2.7T motor in the 2000 A6?

 

Have you thought about O2 sensors?

 

I am told because I am getting the codes for both banks of cylinders that its not the O2 sensors as they would be unlikely to both fail at the same time.

 

I found this post, which seems sorta helpful...
http://www.justanswer.com/questions/...99-audi-a4-1-8
"
The 1136 code is a lean code. This can be caused by a vacuum leak in one of the engine hoses or gaskets or it can be fuel system related. It may be an issue with the fuel pump, pressure regulator, dirty injectors or even just a clogged fuel filter. Since you are not sure as to the maintenance of this vehicle I would probably start by changing the fuel filter and the coolant temp sensor.
"

 

you can actually clean the MAF along with replacing the vacuum hoses.

 

how would you clean it?

 

I stand corrected (sorry):
The MAF Unit is fastened to the Air Filter box via 4 bolts (10 metric).
So you'll have to remove 1 clamp and 4 bolts.
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I have had some problem with my chevy and had to go to the dealer to see the chevy engine codes and rectify the problem.

 

MAF on a 2.7T is held by 2 vandal proof torx screws. You need a torx driver with a hole in the middle to remove the bolts. (If you don't care about the aesthetics, then a vicegrip is your best friend.)

But I would lean toward a vacuum leak for the cause of this problem.