O2 sensor is the only device that'll set off the "check engine" light. You can try running some Techron or other fuel system cleaner through, but likely you need to pop for a new O2 sensor.

Good luck!

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo