Has anyone ever had the smell of ammonia in their car while driving? I noticed this smell about a week ago. Mostly notice it when im on the highway with a window or sunroof cracked mostly when first starting the car after a long time(in the morning). Could it be the gas im using(Shell and BP) or could there be another problem? Also i get more than the usual sulfur smell while driving sometimes. Could my cat/s be bad or goin bad?

 

Not sure... Could be a small exhaust leak close to the engine... Never heard anyone refer to it as an ammonia like smell...