Quickly to start off, I have an Audi A6 2006 with a 3.2V6 Engine.

It has insanely high miles for its year (139,000)

Earlier it was just fine, I went and got an emission test done, no lights were on and I passed.

It said I needed to get fuel so I drove to a Cheveron and put in 30 dollars worth of '92' gas.

Right when I started my car up right after, the check engine light comes on.
So that is my first problem. My second problem..........

When I start my car, I twist the key and when I release it, there's about a 2 second delay before the engine starts running. What are some possible things that might be wrong with my audi?

 

The MIL may be due to not putting the gas cap on fully. Remove it and check the gasket, if it looks OK reinstall it and see if the light goes out, it may not go out right away, you may have to drive it some. You can take it to most auto parts stores and they can read the error code at no cost and tell you the fault. Even better, get a VAG-COM and you can read it yourself and get a lot more detailed information.

I never use the key so I do not know what is normal for starting the car but if there is a fault again the VAG-COM will tell you the problem. It is a worthwhile $350 investment.

 

Not insanely high. 139k/6 = 23k year. 206k/9k = 22.9 year. And I rarely drive it the last seven summers summer because I have a couple Crossfires. Have the codes read for free at an Autozone or equivalent and post them.