I have a 86 rx 7 rotarty engine before all this happen the car was fine the clutch went out so my friend change the clutch and the thermostat the car was over heating and when he start it the car red line 7000 rpm and stay there the gas pedal is not stuck and I don't know why the only thing I can think of is the throttle is stuck in the throttle body so I was going to change the throttle body but before I do does any one know why .

Don't know about rotary engine but this can happen on piston engines if the intake gasket is not sealing

Thank I will check that but I think it it was not sealing it would not red line that hight anyone else has any other idea