Yesterday I got into my Audi a4 wagon and turned the car on, I noticed a clicking noise coming from the left side of my dash. I thought that noise was odd since if didn't stop for a long time, and I thought maybe I might be having a issue with one of my relays. I started to get on the onramp of the freeway and I noticed everytime it accelerated the car would shake, kind of like it was not getting enough gas/oxygen or something. The CHECK engine light immediately came on and so I exited the freeway and took the back streets home. The next day I started up the car and now both the check engine light and also the EPC light is on (the clicking behind the dash continues). DOES ANYONE KNOW WHAT COULD BE WRONG? Thank You.