Thanks for the help....it is only while in town. I have had it to the dealer 3X for this but can't find any leaks. I love this truck but I still love my other truck for MX racing!!!! Ford E350 box van 7.3 4" stainless exhaust, banks chip 250,000 miles no polution junk and running strong.Anybody ever get a BAD smell in their 6.7 trucks ????? I believe it is only when DPF is burning off....it is intermintent but smells so bad I have to put windows down. Of course dealer can't reproduce ths issue. Truck only has 20,000 miles
Is the truck bone stock?
I've been all over these trucks. And familiar with the burn off process.
To raise the temp for burn off the engine injects fuel into the exhaust stroke. It would be impossible to get an oder from there. Look way back on the fuel rail near the fire wall and see if you can see wet places. You might want to feel back there with your fingers.
The other place to look is at the CP3 (Injector Pump) Check all the fittings.
Also pull the dip stick and smell the oil