I have an 89 camaro that seems to accelerate on its own. This generally happens the first time I drive it each day. It ran great until I changed the radiator, oil pressure sensor, and temp switch. The car starts fine and then as i pull out and give it a little gas, the rpms go to about 2000 then I shift to 2nd and give it a little gas and the rpms jump to 4000 or higher. I have to shut the car off to keep from going higher. Once I get up to speed I can keep the rpms down by downshifting but then end up going faster. I really dont know where to look. Any help would be greatly appreciated.