According to fueleconomy.gov: A 2WD Toyota 4Runner can get 16 MPG City and 19 MPG Highway. A 4WD Toyota 4Runner can get 14 MPG City and 17 MPG Highway.
1979 - 1983 2wd and 4wd will for sure
Yes
Since you do not have manual hub differtials you are hearing the electric motor dis-engaging the front diff from the drive shafts and trany...
4wd or 2wd?
The 1997 Toyota 4-Runner automatic transmission requires: 2.2 quarts of fluid if it's a 4WD 1.7 quarts of fluid if it's a 2WD The recommended fluid type is Dexron III (or Toyota T-IV)
Acr30 = 2wd acr40 = 4wd
The curb weight of a 4Runner is around 4600 lbs. Need the year and if it's a 4wd to be more specific.
6500 lbs for 2wd; 6300 lbs for 4WD
You can shift to 4wd (4 hi) at any time below 80 km/h.
Linkage is probably sticking or seized
The throttle position sensor on a 1999 Toyota 4Runner is located by the throttle body. It will be mounted near the throttle cable.