Ok, so my bro's '89 lude started acting funny a couple months ago... it kept on dying really frequently even after replacing battery, and one day it just out of nowhere would not go past 3000 rpms... and now it's just sitting in the yard and everytime we jump it, it runs for awhile... but as soon as we disconnect the jumper cables it completely dies out... i was thinking it might be an alternator problem, but we replaced the alternator about 2 months before all this started happening... it might be one thing or a combination of more problems.. any clue as to what might be wrong? thanks

 

You sure they grounds are good?

 

i have no idea lol... how do you check for that?