My car goes constantly up and down like this when i accelerate, as if it is changing gears back and forth.. what coulld be wrong?
why does it at speeds over 60 mph goes up to 3000 RPM then goes down to 2800 RPM on 1998 Lexus GS300
You could have a torque converter problem. Also, the transmission fluid could be degraded to the point it is effecting the transmission. Has the fluid ever been changed? Do you have an overdrive button on the shifter? If it does shut off the overdrive and see if it acts the same.