What can cause of high RPM but car does not accelerate? is it my transmission slipping?. i have new clutch installed in my car.the pedal feels normal.. its just when the weather is really hot like 90 and when i step on the gas to pass someone on the freeway the rpm shoots up really high up to 5k but the car is not accelerating at all. oh and my car has 160k mileage on it.