I have heard of pinholes at y-pipes tripping the ecu on some 350's , could be clogged cats ; but the car idles very quietly and smooth leading me to think otherwise as there is an equal amount of vapor upon cold starts.. been clearing the code for a month and would love to hear what some of you guys think ; my fuel economy has slowly been dropping since I purchased the car from 20 to just under 17mpg and i drive like a grandpa maybe 3 times a week... ? I'm going to start with the bank 1 sensor 1 02 sensor and likely spark plugs and and a fuel system cleaning...
