You could always start smoking in it. At least it would be your stink. Make sure you leave the windows down on hot days, esp if the inside is wet. found these online:

Some odors seem impossible to get rid of, but there are a few tricks that are extremely effective. After the mess has been cleaned and dried, set an open bag of charcoal in the car. It is considered to be one of the best natural products to get rid of odors. Another household item that works great against stained odor is white vinegar. Set a bowl of white vinegar in your car and let it sit undisturbed. Let me know if this helps...

I had a problem with a smell in the carpet, bought 12 boxes of baking soda and dumped all over carpet (makes a mess if the carpet is damp) stirred all around and let it sit for 2 days, and repeated. All the smells are gone now....good luck!