My 1999 CR-V with 175000 miles started to show the CEL and code reader says catalytic efficiency low one bank. I can smell fuel and tailpipe is rich with soot. Question: besides changing to another new cat (done 30,000 miles ago) and doing a tune up of changing the sparkplugs, distributor cap/rotor, what else can be adjusted? I believe the 10%ethanol gasoline sold today is a cause of the CEL and mixture need to be adjusted. How and where do I start.:banghead: