1997 740il problems

I have a check engine light on. I went to a mechanic and he tested it on his computer. It gives me the following problems
1. (p0133b) OS B1 S1 slow responce
2. (p0302) Cylynder #2 misfire detected
3. (p0430) Cat effic Bellow threshhold(bank 2)
4. (p1174) Manufactured Controoled Fuel and air metering

I just changed all my sparkplugs and my OS2 sensors and i still get these mgs what do they mean? and which cylinder is #2 if you open the hood and face the engine? My fuel economy is horrible(9mpgs) what can i do to fix these things?

I know I'm late, but have your cat. converters looked at. I have A 1998 740il and had the same problems which turned out to be my converters were stopped up and no good.