Exhuast smell in cab
 

I can smell exhuast in my cab only when the heater is on when im stopped but when im driving with the heater on i dont smell it. i lifted the hood and i can smell it, i think i might need a new exhaust flange gasket the smell is close to the blower, any ideas on what else it might be?

Gaskets on you heater box are bad. you should only get air into your heater from the cowl.

Secondly, you have an exaust leak in your engine compartment which should be fixed as well.

Some people mistake a smell in the cab as an exhaust smell, when it sometimes is the smell of the blowby gases coming out of a worn out engine, or a engine where someone has monkeyed with the PCV system, usually with chrome aircleaners, valve covers and breathers.

good point...

My '89 F150 with 68k miles has that problem, but not all the time....