Smell at startup
New Camaro owner here. 2001 M6 with 54,000 miles. I notice that sometimes when I start the car there is a smell that lingers for a couple minutes. It doesn't smell like gas or burning oil, but something definitely petroleum-based. The car is pretty much stock, with the exception of an SLP lid, SLP MAF, and catback (which I installed a few days ago, but the smell was there before the catback).
The previous owner ran full synthetic motor oil, and everything looked good as far as levels. Can a mostly stock car run rich at idle? Just curious if you guys have seen this before and can offer any suggestions. Thank you.
P.S. After it warms up, the smell is non-existent.