I'm having issues recently with a 2008 Pontiac Grand Prix GXP.
A few days ago, as we are pulling out of a parking spot, there is a loud pop and everything dies. The car shuts off, it has no electrical, no hydraulics. It is just dead.
After about 10 minutes, I hear something whining like a fuel pump. So, I put the key in, turn it, and it starts. No check engine lights, no codes, nothing.
We start driving. In the middle of an intersection, we hear bam, a loud pop, and everything shuts off. This time we had to call a tow truck because it didn't come back on.
At the dealership, it is found we have loose connections to the battery. As the is moving the loose cable around, the windshield wipers and the security system begin flipping out. (But, that situation hasn't been repeated.) The guy tightens the connection. We drive off.
Last night, we took a short trip. It started fine and drove fine both times.
Once we got home, I turned the car off and I went to lock it, but it didn't respond. I opened the car door and it had no lights, no power. I turned the key and it didn't start. I checked all the connections to the battery and all of them were still tight and didn't move.
This morning, I hit the key fob to unlock the doors and they unlock. It starts up and runs fine. The radio has been reset like the battery was disconnected.
What advice can you give me?