Brand new to the forum and have a problem. My mechanic coded the car and it came back as over advancing. He said it has something to do with a cam shaft adjustment valve. He said he doesn't want to get into something he doesn't know.

I called a foreign car dealer and he said the timing chain could be stretched. Has anyone had this problem? The car is an Audi A4 2006 Quatro 4 cyl with about 80K on it.

 

If the chain was stretched, the cam timing would be retarded, not advanced.
I would SUSPECT the oil control rings on the cam adjuster housing are broken. This is the big housing on the rear of the head, with the vacuum pump attached to the back of the housing. When I was an Audi tech, ran into the problem quite a few times.
Inside there are 3 rings (basically like small piston rings) that that fit into the camshaft adjuster to direct oil to the actuator that's attached to the camshaft. One or more of them can crack and then the cam can't be adjusted anymore. If all testing with a scanner shows no obvious fault such as the solenoid valve, etc, the only real way to check the rings is to actually pull the housing off and do a visual inspection. Bad news is, the rings aren't available separately (far as I know), only with the housing assy and it's a tad on the $$$$ side.

 

End result and I don't know how this happens. The car codes at Audi for low oil pressure. They recommend an oil and filter change so I agree. They road test the car and no more problem engine light off. They said the oil filter was heavily clogged and was an after market oil filter not an Audi one. $290 later I am running good. How do you go from a mechanic telling you that you need a camshaft valve to this? If the initial mechanic took the job I would have been in for huge cash. So I guess the dealer ended up being a good choice which many times is not the case.