These faults are tricky if they can't be duplicated for a tech. You can start with the basics and see if you can fix it yourself. 1) Check the battery connections and hold-down. Look carefully at the positive cable, if it's frayed it will have to be replaced. If it has white or green gunk on it, a wash with 2 tablespoons of baking soda in 1 cup of hot water will clean the gunk. Be sure to dry the battery after you're finished. Coat the terminals with petroleum jelly or grease AFTER you tighten the battery terminals. 2) Make sure the battery hold-down does just that, so the battery can't move when you turn. 3) Make sure the negative cable is clean and tight at both ends.
If this clears up your problem, you've learned that primary electrical connections are often overlooked. If it doesn't, and you or someone you know is a AAA member, ask the local club for a referral to a mechanic. Another source of expertise is your local Vo-Tech or Community College automotive program.