Gear Change Recommendation

I have a 17 Tacoma with a 3" Roughcountry leveling kit. I went went from P245/75R/16's @ upgraded to Nitto Terra Grappler G2's LT295/75R/17's. I expected a loss on my MPG because of the increase in drag. I didnt expect it to go from 19City to 10mpg.

If i swapped out the 3.90 and went with a 4.10 would that help with the mpg and my tranny trying to find certain gears at highway speeds.

 

Shouldn't have dropped that much. Most people with 35s seem to get at least 12mpg. Another dude here has 37s and is getting over 10? Gearing should help, but something is amiss if you're actually at 10mpg.

 

U think its because the tranny is hunting for gears? I know my speedo is off by mph. I was thinking a hypertech tuner would help?

 

Are you factoring your different tire size in your odometer readings. After the size change your odometer is 13% slow. So you need to multiply your fuel economy by 1.13 to get your actual economy if you are not already.

The issue is gearing, you’ve changed it by changing tire sizes. Any other solution like a tuner is a band-aid and will not address the issue. You want a gear change to roughly match your tire size change to get back to OEM gearing. You change by ~13%, meaning your gear change should be similar. If you have 3.90 now, 4.30 would be closest to OEM.