your cam-shafts could be broken pistons could be bad or you could be driveing a ford
That depends on the car. What car are you talking about?
the normal speed of a car is 120 Mph
If your vehicle has an automatic transmission with overdrive, then at speeds above 45 mph, it should be in overdrive, which reduces engine RPM's to save fuel.
Safety feature is tripped, bring in the car to a shop.
How about it shifts into 4 overdrive gears are higher so RPMs come down.
Out 2000 Dodge Neon does 2500 rpms at 60 mph. Grace
Don't know what vehicle you have but that may be as fast as it was designed to go.
Several things it could be, but frankly, if it's that bad, get a mechanic.
It depends on a the gear ratio of the transmission in high gear and the final drive rear axle ratio. Also depends on whether the car has overdrive or not. It also depends on the size tires and wheels mounted on the vehicle. All these factors will determine the rpms at 25 mph.
1800 or so
yes & no if your motor looses compression your car wont go over a limited
around 5 and 6 x 1000 rpms
because you are making the motor run higher rpms therefore using more fuel.