Petro-chemical fume odor from natural gas countertop stove (Not the rotten egg smell added to gas)?

Question

1961 RCA Whirlpool Stainless Cooktop
Works great, looks new
Pilots (2) are burning and appear normal--light and dark blue flame.
But this odor is really noxious--it's like I'm burning some bad diesel fuel or something. Nothing was boiled over, the stove is very clean. No changes. I've got a CO detector pugged in near--registering 0.0
We are leaving the external exhaust fan on low for now--ANY IDEAS??

No plastic is burning, nothing near the pilots except metal. Smell is definitely from the cooktop, and without the exhaust fan, the smell kind of pools in the kitchen area--you actually kind of walk into it. Wonder if the gas isn't burning correctly....

Answer 1

Is the flame a healthy blue color or is it yellow? there is a system in the burner that mixes gas and air, sounds that there is something wrong with the gas-air mixture. I f you don't have experience with gas burners better have a professional solve the problem, you could cause an explosion or fire.

Answer 2

The first thing I would check was whether plastic had blown into the pilot light area and one of the two was cooking the remains of the plastic. As obnoxious as it sounds, use your nose to find out if the fumes are worse near the ceiling or the floor and see if you can track from the less worse (lighter smell) and localize the smell. Is there any chance something died in shell of the cooktop?