I was driving down the road at 75 mph when the check engine light came on. Then, no matter how far down I pushed the gas pedal it gradually lost more and more power and wouldn't go over 40 mph. After about 30 minutes of driving to get home it was down to only being able to drive in first gear with the engine knocking and sputtering. I made it home, let the car sit for about a half hour and then tried starting it. It started back up easily and when I gave it some gas it ran as smooth as it did before the check engine light came on. Should I try driving it again? Haven't got a chance to test for codes yet. What the hell happened?