It seems that everytime I run the hvac in my 1999 4.6 f-150 I end up smelling exhaust fumes... I always run the a/c on max with the windows completely up and if I get behind or any near a vehicle I breath exhaust. Not to mention in the heating mode in the winter it will really choke you up......I took it to the dealer back when it was still under warranty and had it completely checked out and was told it was functioning normal.(yeah right) I checked under the hood to see if there was any holes or gaps in the firewall and could'nt find any.
If anyone has any ideas and would kind enough to pass them on they would be greatly appreciated!!!!
signed, choken Joe