TPLSTNG

Don't have the onboard computer thing, manual calcs show me averaging 15-16mpg with mostly city driving...and that's driving pretty conservatively. I switched to a K & N air filter and synthetic oil and still get about the same. The few times I have done highway driving with it, it seems to get about 20-21mpg with the cruise set on 72.

This seems to be crazy low for a v6. Gas mileage was the main reason I chose a v6 instead of a v8...well that, AND my propensity for speeding.

Any ideas why its so low??

Nuke

Was your 20-21 MPG highway ALL highway, gas station-to-gas station? It's tough to get an idea if there's a problem if that is with mixed driving.

I've found the sweet spot for fuel economy on my GT is when I cruise between 1500 and 1800 RPM. With 3.55's, that's between about 55 and 68 RPM if I recall. Also, I'd check plugs and tire pressure. Don't rely on 1 or 2 fill-ups to see if things are changing. It takes a lot more data points to truly get a feel if your fuel economy is heading in the right direction.

TPLSTNG

No, the 20-21 was not ALL highway driving...but probably 75% of that tank. It's the 15-16mpg around the city that really has me peeved. I tend to run tire pressure about 3psi above recommended to try and help the mpg.

ODDYSEY

The 4.0's are very touching when it comes to acceleration. If you get into it even a little, your gas mileage drops.

Those don't look like factory rims/tires are they? Do you have a tune?