Been driving mine around without the rear driveshaft lately, identifying as a Honda Basically busted the cap off the slip yoke while greasing it and I have a plan to weld it back in place just haven't gotten around to it.

Will report back if mpg improves in front wheel drive

Hi all. Just a note -- I bought a 2003 v8 and did the following to it right after purchase: new engine air filter (it was really old), new cabin filter, red line ignition cleaner, and cleaned the Mass Airflow Sensor.

These things together allowed me to achieve 24.5mpg (according to the dash computer) over 40 miles on the highway going 55mph in a very flat area with no wind. According to the error that I've seen on the onboard computer, this should easily have put me above 21mph which is not bad at all! But with any wind and higher speeds, the computer usually holds around 20-22mpg (so realistically 17-19mpg). My most recent trip (with wind, hills, higher speeds, several stops) had a confirmed 17.7 mpg highway via odometer calculation.

City has been around 15-16mpg. I did ride behind a semi-truck on another stretch and got the computer up to 25.5 mpg but that was a fluke from drafting hah.

Other than cleaning the MAS (which is very easy, < 5 minute job), make sure your tires are inflated. If you're doing highway driving you can just pump them to the max rating which will reduce rolling resistance at the cost of traction (which shouldn't matter if you're on pavement).

Only thing that reliably works for me is to drive slower.

Are you sure it wasn't fuel line cleaner? :-)

I was getting about 14-14.5 mpg, then I started using non ethanol fuel.. before she died she was showing 17.5 give or take..

That’s interesting

I have a 2003 4.7 and it runs alright. I normally cruise about 35-40 and keep the rpm low, and my drive home today with less traffic after a fresh tune up, i was managing 17.8 on the dash computer....the OBD dongle was reading 28.6 rolling with low rpm. It did manage to settle out about 23mpg when I arrived home. It was only 5 miles, but lower rpm's seem to help.

Haha yes you're probably right. I believe the actual name is "Red Line (60103) Complete SI-1 Fuel System Cleaner "

So quick update and a sort of guide to hypermiling the 03' V8 SR5 runner. (Full time 4WD)

I'm usually running 85 no ethanol, have a wind deflector over the roof rack, and a K&N Performance Air Filter.

There's a few tricks to it:
(1). Let engine warm fully. I don't think it shifts into overdrive if the engine is too cold.
(2). A/C off
(3). Gentle acceleration. Do NOT get above 2,000 RPM. This means on the interstate you'll be doing between 65-70 MPH. I usually keep it around 67-68 ish. Above 2,000 the mileage takes a nosedive. This is the most important part.
(4). If you really want the best balance the weight properly, I get my best below half but above an 1/8th tank.
(5). Use fresh fuel? I havent experimented with fuel age much but older fuel seems to drag milage down. (We're talking month or so old fuel)
(6). This one could be called cheating, but getting in the airflow behind semis works very well. I can get above 20 with it. You don't have to tailgate, but get in the airflow (but not the turbulent part) and stick there.

This is what I do I average 20 MPG usually, but the highest I've gotten is 24 but that was with no wind and behind a semi.
This may differ as I have an early non-vvti 2UZ-FE that is rocking 20 Y/O cats, holes in the exhaust headers, and so many exhaust leaks its comical.
I do have slightly larger tires. The rims are the wrong offset too and I don't know if that affects the aerodynamics of it. (My rims end at the same point as the fender does.)

"03 V8 AWD here, mine settles on 17.3 MPG on the digital readout whenever I reset it and run a complete tank or two through it. Of course after reset it shows 25, but quickly works it's way back to 17.3 eventually, which is about 2 MPG off real tank mileage. This consistent after 8 years and 70K miles of operation.

This is why I own a Prius Prime as well. 90+ mpg on average.