I have a 2010 rs7 with just under 20,000 miles on it. Car runs fine perfect. All fluid levels are perfect and I even get oil changes every 3000 miles instead of 5000. Has brand new air filter and new cabin air filter. It's not going through vents.

After running for awhile, I can smell a faint plastic like burning smell lately. I even took off the magnet bra thinking it was that but it's not because I still can smell it.

What do you guys think it is? Should I bring it to the dealership or is it normal? I only smell it once I step out of the car. But it goes away in a few.

 

And the reason you're dumping perfectly good oil every 3 Kmiles is what?

Do you have an automatic or manual transmission? Mine's manual and I've not smelt anything at all to date.

 

I guess I'm just old school, most of the time I go atleast 4000 miles.

It's an automatic.

 

Does it smell like a new engine during break-in period? Check your downpipe as well, sometimes a stray plastic bag will go under the car and melt itself onto the pipe.

 

Not really like new engine smell. does sorta smell like a plastic bag burning smell though.

 

You might literally have melted plastic somewhere under the engine. The filters only filter out particles in the air, but they won't stop the smell from coming in.

Periodically, letting fresh air in from outside is a big mistake.

One thing you can do is a tip that I've been doing for years. For your cabin filter, drop an air freshener in there and then slip it back into the compartment and reinstall the glove box. The next time any air runs through your vents, it'll smell nice in a discreet manner.

 

+1 on the plastic bag theory.
But just as a check, have you changed any of the factory installed wiring? (like a new stereo etc)