2001 A4 1.8 T. APR Tune

So this is pretty vague but hopefully somebody can point me in the right direction.

I will be driving the car and all the sudden something starts working properly that obv wasn't before and my engine performance increases. Way better throttle response, smoother running, better acceleration, faster spool up. Just all around much better "the way it should be" !!!! This happens at random times in random condition and I never get a CEL.

Any ideas on what could cause this? It's obv something that would have control in the overall performance of the engine. It's unbelievable how good it runs when this is working properly. A bad sensor? Maybe bad ground or something in the computer? It's something that has full control over the way the engine runs overall.