Have the vehicle checked for trans codes. It is very likely a electrical problem with a sensor. It may be the TPS. Dan
Shifting into a lower gear, most often as you reduce speed.
you can on most, but it is harder on the transmission than downshifting as speed decreases.
with a variable speed switch
speed control switch inside trans
The speed control switch is on the steering wheel.
Yes. But brakes are cheeper than transmissions and engines. Use them
If you mean hunting at idle, the problem is caused by the idle speed being set too high or the idle switch is not properly adjusted. When the throttle is closed as indicated by the idle switch the fuel is cut off by the fuel cut solenoid until the engine speed drops below a preset speed. If the engine speed is higher than that speed and the idle switch is closed there is no fuel for the engine, thus the engine speed drops. When it drops below the preset speed the fuel is turned on and the engine speed goes back up.
A ceiling fan speed control switch is wired the same as an ordinary off- on switch. If it is a replacement, look at the wires connection on the existing switch and connect the new speed control the same way.
Find the control switch located on the steering column. Push the end of the switch in to turn on the cruise control, push again to turn it off. When you get to the speed you want, push down on the switch to set. To coast, pull the switch towards you to disengage. To resume the previous speed, push up on the switch. To adjust speed while driving, push down on the switch to lower speed. Push up on the switch to increase speed. If you just tap the switch up or down, it will adjust the speed in approx. 1 mph increments.
Anenometers usually measure wind speed, but can also measure wind pressure as well.
Vehicle could have a solenoid type switch to increase idle to compensate for load on engine caused by A/C compressor
replace the switch.