I have an 88 iroc with a rebuilt 5.7 tpi 350. when i start the car it idles fine but as soon as i start driving, the rpm's shoot up to 2500-3000 and stay there whenever i have to depress the clutch to stop. if i hold the clutch about halfway out and brake it idles down but i dont want to burn the clutch out. i have no clue what to look for because my knowledge is limited. any help or suggestions would be greatly appreciated.