VW Jetta 1999.5 problems

OK so a few months back my car was sitting for a couple weeks because I didn’t need to use it. I go to use it and it appears the battery is dead. I get someone to jump it and it starts. I drive around and then let it idle for about a half an hour. I turn it off and it won’t restart. Days later I clean the corrosion off one of the posts and tighten the cables. It starts and seems to have no problems. I drive it to and from work a few times. Then one day I drive around doing errands, meaning I didn’t drive too far, but I kept turning it off and starting it. Finally, after a couple of those it just shuts down while I’m driving. The battery light went on and I couldn’t restart it. I sat there for several minutes and went to clean the post a little. After that it started. I drive about 1.5 miles and then it died again, this time I noticed the oil light on. I tried cleaning off the post again, but that didn’t work. I left it parked overnight. The next day it turned back on without a problem and I got it home.

After all that, I decided I needed a new battery. After the installation of the new battery, it started again without a problem. The next day I drove it to work (about 6 miles) and made it there fine. On the way home from work it died again after about 4 miles, I had just gotten off the interstate and pulled up to a red light and it died right at that moment.

After about 15 min of traffic beeping and me sitting there not knowing was to do (At first I tried starting it again a few times but gave up), I tried starting it again and it turned on. I made it the last 2 miles home and turned it off.

A mechanic told me to add a bottle of Iso-heat and fill up the gas tank. It had something to do with the car sitting for a period of time. I made it to the gas station and did just that. He then said to leave the car running idle for an hour and if it stayed on the whole time, it’s good. After about 40 min it died. I tried it again after cleaning the corrosion again but this time it lasted only 20-30 minutes.

Please help me. Some people said it’s the alternator, while other people said that can’t be it it’s the ignition. My car is driving me nuts.

You could have a bad ground connection wherever your battery grounds to. Remove the ground cable and clean up the connection at the other end. While you have it off bend the cable, If you feel any brittleness or crackling replace the cable with a new one.

Take it to an autoparts store and put a load tester on it. This will diagnose an alternator or battery or whatever better.

However check your ground connections as described also.