When any window is down (4dr) I'm getiing exhaust fumes inside the vehicle. The muffler and tailpipe are not leaking. Took it to Ford and they replaced the charcoal cannisters (where are they). And a vapor management valve ? Anyways that didn't fix it. After a hard acceleration or above 75 mph exhaust smell is pretty bad inside. Anybody had this problem or got any ideas
Thanks, Mike

Take it back with your largest ball-peen hammer and be ready to apply said hammer to the desk-jockey. Fumes in the cabin is serious stuff. Carbon monoxide is nothing to mess around with.

I assume you need to be "at speed" for the fumes smell? If you shut off the air system (vents, A/C, etc) then open a window does it still happen? I'd bet that you're sucking air directly in from the engine compartment somehow. With the window open your buddy Venturi is causing a negative pressure in the cabin, and pulling air in through the various holes in the firewall.

Is it possible that the fumes are from spilled oil or steering fluid or something burning off the top of the transmission or headers or etc.?