Rattling in the exhaust most likely due to the catalyst in the catalytic converter breaking down (overheated due to plugging up). It will probably need replaced, (search the net for cheap auto parts wholesalers) check it with infrared heat gun or other temp measuring device. You may try unhooking the battery for ten minutes and letting the ecm go back to it's original programming. True - it will then have to "relearn" your particular driving habits, which in turn will still cost mileage. But if you have checked the obvious (air filter, spark plugs, wires, cap & rotor, oxygen sensors, tire pressures, ect) this may help. You probably know that your still running oversize tires, so some mileage will be affected. I have 30's on my jeep - but still get 15 to 19 mpg. Let me know.
Monday, February 7th, 2011 AT 4:42 AM