BLM's at 140 during cruising...

[darkfa8]

I have been having extremely poor gas mileage in my Turbo Regal. It is mostly stock (engine, turbo, ic). I'm averaging betwen 13-16mpg on the hiway

I am using Testa's blue top chip with my blue top injectors...

Crusing O2s peak out in the 700s, WOT peaks at .790-.830mV

FP is 39psi line off

Fuel pump is Walbro 340m, hotwired, fuel filter replaced, plugs replaced and gapped tight to .035", wires are Taylor, tps is .42 at idle, IAC is ~15 at idle

I'm also using a ls1 maf with the regular translator with all the settings set to "0"

When i installed the injectors I lubbed the o-rings to they would seat, and I didn't push the injectors deep into the intake bores, they are retained with the clip retainers.

I have replaced all vacuum lines and my vacuum at idle is a steady 18 in/hg

I don't blow any smoke under WOT acceleration and have had no knock since at current my boost is low, ~13psi (bad wastegate solenoid possible)

I have visually inspected with a bright light, and my hands my headers as best I can without removing them from the car. I've also listened to them with a stehascope and run tissue over them to hunt doen any cracks...haven't found any...yet

O2 sensor was replaced within the past several months with a GM single wire unti. Battery voltage at cruise is ~13.6vdc

As of late, with East coast weather being clear, low humidity and in the 70s, I've been running between 162*-180* coolant temp.

Any other ideas on what I should look for, test or check into?