The gas mileage on my '04 Honda Odyssey (121K) has recently fallen off tremendously. I used to get 330-350 miles per tank mixed driving. As of late it's dropped to 250-280. I took it in to the dealer for an oil change and they suggested an injector service($160) should cure it. I had about 1/2 a tank and around 180mi at the time. The guy told be to run that tank through to flush out the treatment stuff and then fill as normal. Well on the rest of that tank I ended up at 320 miles. I thought great, fixed! Not so much, next tank 240 (14mpg), worst ever.
With gas at $4gal, any suggestions highly welcomed. TIA