What is the normal rpm at 70mph for this car? Toyota paseo 4 speed automatic

Hello, That vehicle likely has an issue with the torque converter, or a shift solenoid. You are driving on the highway in a 1:1 ratio... this means that overdrive is not engaging. There is a button on the shifter that says O/D on/off. That button, when left on, will allow the transmission to use overdrive, lowering engine speed at highway vehicle speed. When the button is disengaged, the vehicle will stay in 3rd gear... You may also have an issue with that circuit. I recommend having the issue diagnosed by a professional technician, especially if they rebuild transmissions in house. You will consume far more gas at 4000 RPM, and you will also wear your engine out much faster. If the transmission fluid and engine oil have not been changed on time, there is no time better than the present to get maintenance back on track.