s-10 loses electrical power driving

Hi i was just out recently running an errand and my truck stalled out
while i was driving home. I popped the clutch and was able to get it running
again but i noticed the volt meter was jumping all over the place (down to 9 and
back up to 14)...i could feel the power loss. I've notice my meter going
low before with the a/c on and i shut it off and it starts charging the battery
again. The service engine light went on a couple of weeks ago but the
truck behaved normally. It also died completely 100 ft from my house
and i was able to restart it and get in the driveway (sounded like it cranked
over normally). Any ideas?

i would have alt checked at autozone or advanced,or if you got pep boys around you at no cost also have fuel pump tested,and make sure your battery cables are clean....

may have fixed it. cleaned the battery terminals and the ground on the
block. drove it around for about 5 miles...meter stays around 13 volts
and it doesn't fluctuate.