Aquatic Escape

Recently installed a rebuilt 3.0 and magnaflow exhaust with Black Widow exhaust and S & B air intake. I expected a low end power drop with a near no back pressure exhaust. Power is great over 3k rpms. Problem is I have only been getting about 11 mpg around town and from about 2500-3000 rpms power drags then when it hits 3k it is like turbo kicks in. Power surge is more noticeable when a/c is on. I replaced tps and adjusted to specs. When I put in jumper to set timing, there is little to no noticeable difference in idle(same with previous TPS). But when I set timing then pull jumper, the timing drops 2 degrees like it is should. Wondering if I have a vacuum line issue, or maybe an injector issue. Any ideas would be great
Thanks

cbr600rx7

What's your base timing set at?

Aquatic Escape

Initially was running it at 10 degrees, it would drop to 8 without jumper
Just tried bumping to 12 degrees, drops to 10 to see if there is any difference one way or another. Does not appear to make any difference.
Would an exhaust system with very little back pressure cause this?

cbr600rx7

No.....

Janos01

The 3vz-e is not known for good MPG. Ive only had about a max of 16 MPG highway & 12 MPG city. Have you tried to run a fuel additive such as B-12 or Chevron w/Techron to see if MPG increases? Has the fuel filter been changed at all? Is you truck running rich?