electrical problem

My friend just gave me his 89 honda prelude and every once in a while
i will lose all my volts,and my engine starts to backfire and i have
no throttle response.I checked the alternator and it checked out
good.I replaced the battery, still had no luck.But as soon as i put
jumper cables to it it runs fine. If you have any ideas that would be
great .Thank you Justin

 

Some friend!

_How_ did you check the alternator?

Of course, at that point the car is not in motion. Does the problem seem
heat-related? Vibration-related? Does it fail while turning? While
accellerating?

What indication do you see on the dashboard when the failure occurs? Does
the Check Engine light come on? How long does the condition persist? What
brings the voltage back? What works fine when you have the engine problem?
Radio? Headlights? Horn?

 

boy, your description of the problem got me flabbergasted. I have no
idea what is going on there.

but you know what, something tells me that your ignition switch is
f*cked

cheers