92 Tranny Problem?

i have a 92 3.0 2wd that, like everyone else's, gets absolute terrible gas mileage for a v6. i also own an 01 yukon with a 5.3 v8 that gets better mileage than the 4runner.

my question is this: lately it seems that my 4runner has decided to run at higher rpms while on the highway. it will shoot up to 3500 rpms while i'm cruising at around 65 or 70. it seems as though the transmission is not letting the car stay in overdrive or that it can't decide which gear it wants to run in. it's very sluggish accelerating from a standstill, but runs well when you're driving at in-town speeds (20mph - 45mph). i am not sure what's going on and hope someone else can offer a suggestion or 2. the timing belt is about a year and half old, same for plugs, wires and cap. just had a new muffler put on as well as the old one was shot. fuel filter could stand to be changed, but i don't think that would affect the rpm jump.

It may be you need a new thermostat. The transmission shift points are engine-temperature controlled. This would affect your gas mileage also.

I agree, thermostat. The tranny & transfer case are controlled by the ECU. The ECU keeps the RPMs high until it is warmed up. Bad stat bad shifting.

i have a 92 3.0 2wd that, like everyone else's, gets absolute terrible gas mileage for a v6. i also own an 01 yukon with a 5.3 v8 that gets better mileage than the 4runner.

my question is this: lately it seems that my 4runner has decided to run at higher rpms while on the highway. it will shoot up to 3500 rpms while i'm cruising at around 65 or 70. it seems as though the transmission is not letting the car stay in overdrive or that it can't decide which gear it wants to run in. it's very sluggish accelerating from a standstill, but runs well when you're driving at in-town speeds (20mph - 45mph). i am not sure what's going on and hope someone else can offer a suggestion or 2. the timing belt is about a year and half old, same for plugs, wires and cap. just had a new muffler put on as well as the old one was shot. fuel filter could stand to be changed, but i don't think that would affect the rpm jump.
Another newbie here. We also have the same problem with a 1995 3.0 4wd but we replaced the thermostat and still have the problem any more ideas would be appreciated.