In about the last 6 months, starting just before my 50,000 mile major service, the fuel economy on my '04 Club Cab 4.7L auto has been dropping. At the major service we did plugs and everything and more the book says, I had the injectors cleaned with the BG system. I had cleaned the K&N just before the service, and I use only 100% gasoline (or the mileage REALLY drops). I'm thinking maybe the "downstream" cat-con sensor may be going, keeping the mixture too rich. Dump a can of Berryman B-12 ChemTool in the tank, and the mileage improves, for that tankful. I'm not showing a code, my dealer checked the sensor's at the 50K service, but they are just pass/fail. The service writer thinks I have the right idea, but $100+ for sensors to test my theory seems a bit extream. I'll take guesses, wild-ideas, or Voo-Doo at this point. Oh, yes, I ran a couple of cans of Sea-Foam thru it with no apparent improvement. My in-gear idle has dropped from 600 RPM to just above 500 RPM and is slighty rough. Throttle-body cleaning time? Anyone know of a step-by-step pictorial or video on cleaning the 4.7 TB? (I know how to clean a 3.9 or 5.2 Magnum, but that's not much help). :withstupi
