Exhaust smell in cabin

I have a 2000 jetta which recently started to smell of exhaust in the cabin while idling. I've been using the recirculatory air button while idling which blocks the smell, but this is annoying and fogs up my windows.

On top of this, when I got in my car yesterday after work (before starting the car) there was a very strong odor in the cabin. The only way I can think to describe it is paint fumes from painting a car (or a mix of exhaust and nail polish). It still smelled like it when I drove it again last night and this morning. And no, there's nothing in my car that could be causing the odor...I checked.

Any ideas?

For the record, this all started after my VW dealer replaced my spark plugs and wires. It's probably not connected, but thought you should know.

I to have this problem! 1998 Jetta GT. Anybody figure this out? It's only noticable when you stop