I am stumped on how to diagnose a rotten egg smell inside the cab only... started two days ago but no check engine light to check for a code... I googled it and two things stood out ..1-running too rich and bad gas millage... 2-catalytic converter might be bad ...??? anybody ever have this problem??

 

dead mouse ? You should have more smell outside if the gas/ converter / etc is the problem. Are you using any antifreeze ? Level still full ?

 

It's only on the inside of the cab ... smells like sulfur ..coolant is fine , battery fine , don't hear an exhaust leak but the gas mileage is down ...just had the transmission rebuilt a week ago... no leaks and no engine light ...