Car problem

Couple of questions....how many miles does this vehicle have...and ref. the RPMs, is it when the vehicle's trans. is/ isn't engaged ? If the vehicle has high mileage the problem maybe the catalytic converter. Oftentimes this part will become clogged and not allow free flow of the exhaust system. You can check by placing your hand over the exhaust pipe or place/tape a piece of paper over the pipe to determine free flow. If there is free air flow while idling and no higher rpms during vehicle movement the problems could be timing or injectors are not flowing properly. Good Luck