Hey!!
You say this smell is noticeable under load. Check to make sure you do not have a leaking Fuel Injector! Best way to appraise this.... shut hot engine down after trip and open hood. Listen for any hissing and obviously if there is any gas smell under the hood. Locate the issue. You may have to be in a garage if the surrounding area is noisy. A leaking fuel injector is a fire risk big time!!! Injector "O" rings harden up with age. Could be...on an older car.
JR