Cm871 help!

[TwinD]

I made the mistake of buying a demandated truck and after reading article after article on this site I am 110% sure my issues are in the the tune and hopefully that's all for now. I have a 2011 peterbilt 386 with the cm871 and she has poor fuel mileage and low boost. Fuel mileage is usually in the mid 5s and boost at max gets up to maybe 17. No boost leaks, turbo is new from a certified holset shop(purchased just before I discovered everyone's recommendation on here), and actuator went out and was replaced just one week later(last week). I have the ebay special insite on the way and will be here by Friday. Can some please help me and tell me what I'm looking for and how I can get the @m*m^2 into my truck? Also yes the cans are all completely empty, egr is still there but everything is blocked off, no lights on dash, and currently no codes, on my dash however under engine info it says "engine model 2007 isx1" which leds me to think it has a cm870 tune but i have absolutely no idea truthfully thats just my assumption. I'd greatly appreciate any and all tips, tricks, and advice