2000 Jeep Cherokee Q&A

2000 Jeep Cherokee Question: What things can I check, since I replace all things?

My son drove in to town and the car was fine, he filled the up the jeep and after that it made a loud noise , would drive over 30mph. It was jumping and running really ruff. I took it to a mechanic, he said it needed a new alternator, battery, and serpintine belt. Replaced all, Still only registering 9volts, running really ruff. Light on says check guages, sounds bad, no over heating or anything. -
Answer 1
seek a 2nd opinion. this is an issue that needs to be looked at instead of guessing could be alot of things -
Answer 2
Make sure he didn't put diesel fuel in it. Have somebody else (ask around for references) diagnose the electrical system! -