1988 Other Mitsubishi Models High erratic idle and coolant r

Hi scocarl21,

Thank you for the donation.

Let us start with the idling. High idling speed is either due to
1. Improper idling adjustment. Check the Idle speed adjust screw.
2. Idle Speed Control (ISC). Check if the ISC is faulty. Insufficient coolant can cause it to malfunction as well.

Lack of power and improper idling speed could be related. I would suggest checking the ignition timiing.

Overheating.
What type of cooling fan is your vehicle equipped with? Electrical or mechanical with cluth?

Are there any coolant losses? Check the radiator coolant level at cold engine. Are the radiator cap seals in good condition? A bad radiator cap would allow coolant to be pushed out to the reserve tank when the coolant heats up.