replaced cat + o2 sensors
So, I got a brand new cat and replaced the O2 sensors, it's all done...but nothing changed. The mileage still sucks, I don't know what else could be doing it? My CEL isn't on, so it's not like the MAF is dead or something. I've replaced the spark plugs recently, the oil has been changed recently, the filter is fine, what can I do? I've been trying to improve my mileage forever and I'm just about ready to give up.