Quote Originally Posted by ZEUS
Is it maybe a leak somewhere? Your tires also alter your speedo and odometer so you might be getting worse than 9 mph in actuality... not that you wanted to hear that... sorry! I hope you get it figured out soon.
Zeus,
Pardon me for sayin' so, but I've had a few fuel leak issues & if it was enough to decrease mileage, the olfactory sensor (nose ) would pick it up.

As for tires...larger tires rotate fewer times per mile, putting less numbers on the odo. ...for a point of reference, 33's are about 10% larger than stock.
When I figure mileage, I add 10% to whatever's on the trip & then divide by gallons...& it's still pretty dismal.