[thstone]

The good thing about a scent is that it can be tracked down...

Does the odor occur while the car is stationary or when its moving? Or both?

You say that there is no odor from the exhaust tips yet there is a strong smell in the interior. Remove the engine cover to see if that re-creates the odor? If so, the engine cover may not be sealing properly.

Do the same for the front engine cover behind the seats? Same odor when removed? Might not be sealing properly.

Lay on the ground next to the car by the doors when the engine is idling - any odor? Might be an exhaust leak from the exhaust manifold or exhaust system.

A little detective work should be able to identify the source.