The engine coolant level is low. Add more and the pump will be able to move coolant at the lower rpms.
5 to 6 hundred rpms. Is recommended idle
I think these vehicles are just designed that way. My 1.8L 1988 Pulsar with manual 5 speed is about the same - just under 4000 rpm around 70MPH in 5th gear. I also noticed that the indicated speed is higher than actual by about 5-10 MPH. Just cruising with freeway traffic, my speedometer indicates 80 MPH when I know everyone is around 70.
I believe that the torque specs on it is 137 ft-lbs at 2400 rpms. Hope this helped!
i got mine up to 145mph so far... at 6500 rpms. mods= k&n cold air intake
about 12, 13,000 RPMS.
lower rpms use less gas higher rpms have more power
stopped up exhaust system
If you have an engine that idles at 6000 rpms, you need to have it checked - immediately. Around 750 rpms would be normal.
Have the catalytic converter checked, probably stopped up.
ask a mechanic.
maybe your rpms gauge is broken.get it looked at by a professional