ClutchI think i have the same problem too. When i am in 3rd or 4th and put some pressure on the gas pedal the RPMs would just go up and my speedometer would slowly go up aswell. It just feels or sounds like i am just revving the engine. It would do this even my car has been warmed up.
valve lash, 99 and newer cars need the shims adjusted and older cars need the hydraulic lifters cleaned or replacedAnother thing is i hear a clicking sound in my engine bay whenever i start up the car and let it run for a bit and when i am stopped at lights/stop signs. I don't hear it when i am on the move though.