Added Magnaflow exhaust and.....
I had a straight exhaust on this thing, 2005 FX4 Dually Crew Cab, and it dumped before the rear axle. Loved the sound and rap when I'd get on it but the fumes and worrying about annoying the neighbors made me grab a complete stainless Magnaflow with rear exit and install it.
Now, I've noticed it won't boost more than a tad bit over 20, but before I could easily see 30 under WOT. Also, I can't break the tires loose like I did before, but in turn, the caveat has been improved MPG. About 2mpg in fact.
WTF? Do I need to "reset" everything after adding the exhaust since I've introduced backpressure back into the sytem?
Any advice or ideas? Oh and I'm not chipped or tuned. Just an EGR bypass of the up-pipe.