Also base timing will be about 8 degrees before top dead center with full timing at 28 to 32 degrees before top dead center. Idle should be about 650rpm in gear, any higher can cause problems with the shift interupt switch making it hard to pull out of gear. Your motor is most likely a 2.5 liter gm engine rated at 120hp. Cruising rpm will be between 3000 and 3500 rpm. Full throttle should be around 4400 rpm. Check your intermediate shift cable (goes from shift plate to outdrive) for sticking. This plate also holds the shift interupt switch. Make sure this switch is not sticking either.