1999 Chevy Camaro - Issues

1999 Chevy Camaro v6 93,000– When I start it in the morning it jumps like it wants to take off, after it starts the rpm gauge is a 1 when in park position and it vibrates slightly. It makes a rough noise coming from the engine, as though you were driving on a dirt road. While driving down the highway you can feel a sputter in the gas pedal at 55-65mph. On turns the car loses control. Got a pre alignment and alignment check, all front suspension parts were solid; no angles were out of specification. Another problem is I added antifreeze to the radiator and coolant recovery tank but my heater doesn’t shoot any heat out. Is it the thermostat? I noticed when I switch the heater to on position the car changes (you can feel it in the gas pedal) or when I change from low heat to high heat, which neither produce heat.