So I just got the car back from my mechanic about 3 weeks ago. Had the fuel pump AND the water pump replaced along with some other minor things (wheel hub assembly, wipers, etc) The car began to stall randomly but would start again with a little hesitation. The other day I was making a turn and upon completing the turn it stalled for a few seconds then came back on by itself...also my check engine light popped on at this time. Today after I got to work it stalled in the parking lot. This time it was DEAD. No clicking when I turned the key no lights worked NOTHING. I let it sit for a few minutes then jiggled the battery under the hood. My lights popped on (guess I'd left them on for the minute I was out of the car) and I tried to start it. All my accessory lights came on but when I went to start the engine everything died again. No clicks lights nothing. I let it sit again for about 15 minutes and then jiggled the battery again. This time to car started although it sounded like it struggled and I was able to move it into a parking space. And my check engine light is also off now.

I had some battery issues a few months ago with corrosion and whatnot. I replaced the terminals cleaned everything up pretty good and put a battery in that was from a Chevy Venture minivan. My in laws just bought the battery but totaled the car and salvaged the battery. It'd been fine for months but now it seems to randomly stall and give me battery issues. I've also noticed that when IDLING my RPMs sit around 500 - 600. It seems a little low to me but never thought anything of it.

I've tried looking at other forums but all people's problems seem to focus on the battery or the idling issue. I'm having all these issues at once! I've put a lot of money into this car because I LOVE Dodge but the facts are it's 16 years old has 190,000 miles in it and I now have a newborn son and cannot afford to keep fixing things when something else goes wrong a month later.

Am I looking at a busted alternator? Fried wiring harness from putting in a higher rated battery than what my car calls for? I would just like some advice and direction before I decide to fix it or junk it. Thanks in advance to anyone who can help!

Edit: just tried to start it for my lunch break and it went without a hitch. Tried it again after lunch and now it won't start. Jiggling the battery only gives me accessory power until I try to start the engine then everything goes dead.