Mazda RX8 Lemon?

We understand that your problem is:
I own a 2004 Mazda RX8. My vehicle is currently at a Mazda dealership for repairs originally stemming from a gas odor and stalling engine. It's been there for 3-weeks. I've picked the car up 2x, Both times, told it was fixed. So far, I've paid for new coils, catalytic converters, and even a new engine. What do I do? I had the car towed back last night after having it back 1 1/2 days the gas odor returned and car stalled. Just like at the start of these problems.