95 Gmc True Dual Exhaust

[up4x4]

Three years ago i installed true duals on my 95 GMC 350, initially i had headers, 2 1/2" pipe, no cats and Magnaflow straight thru mufflers. then i got EGR codes and lost power and mileage. So being told i had back pressure problems i installed Magnaflow high flow cats, went with 2" pipe from headers to mufflers and very little change. So then i replaced the straight thru mufflers with glass packs. These changes did help some, but the power and mileage is still worse than what i had with factory set up. Should i also change tail pipes over to 2", or just scrap the whole system and go back to factory? My main concern is highway driving, any time the engine is under even the slightest load especially up hill my tranny is always down shifting to try to compensate for lack of power. My HWY MPG with factory was 15-16 average, now i'm around 11-13. Anyone else experience this type of problem or have any other suggestions?

[Nytemare]

Replace your mufflers with something with baffles in there...or get a big baffled resonator. This is what happens when you go with too free flowing of an exhaust. In the high RPM range you probably gained a butt load of power though.

 

Do you have an X-pipe or H-pipe in there??

[waynet]

had an engine light come on, and was close to the dealership, they said the code was ( lean bank 2) i left the dealer and my truck quit running, iam stuck out in the boonies.

when it quit running it acted like it was running out of gas, ive also do not hear the fuel pump run when i turn the key on and last i noticed the fuel gauge will not show level when the key is turned on. today i went back and tried to start it , it ran for 30 secs and will not start, i really could use some advise thanks wayne. 2002 4x4 extended cab gmc