94 4Runner was overheating, replaced t-stat and water pump now no power...???

Did you Check the ignition timing ??? maybe it's burn Head gasket

I agree with checking the head gasket out, but was wondering how long it took before the water temperature light inside the cab went on, you may have a faulty temp sensor as well , if you are not seeing the light before the car gets to the point of over heating there is probably a problem with that as well. check your oil stick to see if it has a frothy oil , from coolant entering in to it , by way of getting through a broken head gasket. but sorry to say it does sound like a head gasket has been broken. but because he was replacing the water pump there is a good chance the timing is off so that would be where I started first.and one more thing because the radiator caps are made for pressure of a certain poundage to hold pressure in the radiator, check to see if the rubber on it looks cracked or badly worn , if so replace it, if its not holding the right poundage it will over heat .