Leaving the dealer in "Limp Mode"

Among the maintenance work performed during my service was a valve adjustment.  At that time I had almost no knowledge of a "vanos" component on the motor.  My car remained at the dealer for several days.  When I picked it up, I drove a couple of miles to the interstate and as I got up to speed, I realized the car was running rough.  I looked at the gas gauge and realized the tank was nearly empty.  I drove across the bridge towards tampa hoping not to get stranded on the bridge.  By the time I made it to the Westshore Boulevard in Tampa, my dream car operating in what I have since learned was "limp mode."  I called the assistant service manager at the dealer and told her I thought I was running out of gas, but feared maybe something else was wrong.  I filled up my car with gas, but the car remained in "limp mode".  I called the assistant service manager back and she told me sometimes it took a while to return to normal after running so low on gas and drive it a bit further.  She told me if it did not resolve,  I should return the car to the dealer.  It did not resolve, so I returned the car to the dealer.