[V6-12v] Strange new exhaust smell

[Craig D. Niederst]

For about the past month, I have had a strange exhaust smell from my '92 100S. It smells like burnt coffee beans (not exactly the odor, but that's as close as I can describe it). I originally thought it was just some sunflower seeds that mice had stowed in the engine bay that I attempted to blow out and happened to get onto the exhaust or other hot engine surface. But upon closer inspection, the smell is definitely coming from the exhaust, and not the engine bay. I have changed the oil in that time period (from 10W30 Syntec to 10W30 Quaker State Higher Mileage) to see if it helps my oil consumption issues (~1 qt per 500 miles), so I was wondering if it may have something to do with it. I have used this same Quaker State oil in a Honda Accord and Plymouth Voyager, and they do not have this odor. Any ideas? 

Craig
'92 100S (108k)
'86 CGT (234k)