2250 issues...need advice

[Beaver]

Ok, I bought this truck about 2 months ago and I have already replaced the imap and delta-p but I am having some issues.

When I use the jake brakes they are kinda weak and make the truck shake pretty bad. Also having low power and low mpg issues. It's only got about 30k on the piston swap recall.
Turbo spools up smoothly to about 35psi when I'm on it. Also, on the flats my mpg's are really good. Not sure what other info may help but thanks in advance!

Oh! 1more thing, I had a good bit of algea when I bought it but I've been treating the fuel with that bio-chem stuff and changing filters.