Added 5" exhaust lost power
 

I added a 5" magnaflow performance exhaust on my 03 f250 lariart crew long bed 7.3 powerstroke. I put the magnaflow muffler on too is this a mistake should I just put a straight pipe in I was worried if I didnt I would lose restriction and low end power which is exactly what happen how can I fix this problem without dumping a butt load in the engine.

are not getting enought back pressuer put the factory pipe back on at the turbo and leave about a foot so it has enought back pressure the that should fix the problum.