Bad smelling exhaust

Is your engine a diesel? It is my understanding that diesel engines put out that smell from the diesel fuel. I have never experienced that with any other type of engine. I am curious now that you brought that up. What type of car do you drive? I will watch to see what replies you get to this so I can learn more.

Where are you driving over 70 MPH? I would sure like to drive that fast if I could. On a more serious note, it sounds to me as if you may have a clogged catalytic converter. This is usually caused by running leaded gas in a vehicle that was designed to run on unleaded gas. I seriously doubt that there is any place in this country that you can get leaded gas any longer, though. Tell me what this vehicle is and I may be able to help more. Are you putting a lead additive in it? I hope this helps.