Hello, I'm new here. Here is a tough one for you. I couldn't find answers in previous threads. I bought a tired 2006 V6 a couple years ago (150k miles) to learn a bit about mechanics, and oh boy I have learned a lot with this car.

Here is how the last problem appeared. I started to hear an intermittent rattling noise (especially at low RPM), which lasted a couple weeks (couldn't locate the source, but I think it was louder on the passenger side, under the car), then the noise stopped but...

Car Doesn't start or stalls immediately, I tried everything.