willyt4r

Uphill a 11% increase in MPG distance 292 miles
Downhill 16% increase in MPG distance 292 miles made it home on one tank

Sturmcrow

I delayed in posting my results because they were not what I wanted to see. I guess sometimes that happens.

I was running late on my way up there, so did not have a chance to adjust the idle timing along the way. Regardless, going from sea level to Las Vegas on 10* BTDC, I got 19.2 MPG. That was with me keeping the speedometer pegged at 70 the whole way and using the A/C for 90% of it. I have 28" tires (the xxx xx r15 stock tires)

Before heading home, I adjusted the idle timing to 15* BTDC. Going from Las Vegas to sea level, I got 18.5 MPG. The speedometer was kept at 70, but the A/C was not used at all. Naturally, prevailing winds are west to east, so could have had an effect.

On average, going home I should have seen better fuel economy because I was going downhill and was not using the A/C. I should have seen lower fuel economy due to assumed headwinds.

Going to Las Vegas, I should have had lower fuel economy because I was going uphill and probably higher fuel economy because I had a tailwind. I also hit a lot more traffic, which would bring the mpg's down.

All in all, I think my experiment was a wash. My gut instinct is that increasing the idle timing advance actually decreased my fuel economy (based on my own perception of headwind, tailwind, traffic, and urgency to get up hills). FWIW, I set my base timing back to 10* BTDC when I got home. I have used 91 octane for all fill-ups since November.

I also want to add that these 'Yota trucks are awesome! My bro has a 1999 Wrangler with a lockright in the rear and 31" tires. I had no trouble following him wherever he went on the trails at Logandale. There was one obstacle that he high-centered on, so I ended up taking a different path around the big rock that he probably could not have made. After the wheeling, I ended up rolling out my sleeping pad in the truck bed and sleeping under the stars with a thin blanket. It was an awesome trip. I plan to start a build thread soon, so keep an eye out for that. Hint, hint, I have a front locker and a rear LSD just looking for a home in my differentials.

I also want to add that I removed my front sway bar before the 1.5 hour trip to Logandale, NV from Las Vegas. I was a little worried about the ride, and we did encounter a stiff cross breeze. I literally felt no change in the handling. The sway bar stayed in the bed of the truck all the way back to Orange County, and again, no change whatsoever. I had read other folks posting that they removed the sway bar and had no change in handling, but I was skeptical. Seriously, if you have a deep socket set, and are on the fence, go do it right now. You might have more of an effect if your alignment is off or you have a standard cab, but the increase in IFS flex is well worth it. My sway bar will be hanging in the garage until I sell the truck, or need some scrap iron.