Recently dropped the cats among other uprgades, figured it was responsible for the light smell of fuel. Then this week, started noticing light gray smoke coming from my exhaust when I was stopped at intersections. Probably smokes slightly too when I am driving, just don't notice it. What caught my attention was a dip in MPG's from 20.2 last week to 12.8 this week. Burning fuel? Mechanic is looking at it in a few hours, just wanted to see if anyone else has experienced anything similar and what you found. Anything I might have him specifically check? He knows the car pretty well, but any advice I can give him couldn't hurt. These Z's are another animal. Thanks