Ive got a l67 in my 97 firebird. I am using a stock 99 GS tune with the torque management removed. I have no EGR, no cat, cone air filter, 180degree tstat and 3" manifold back exhaust with a good muffler.
I have been getting kinda crappy gas milage. Mixed 75% highway 25% city is like 16MPG. Got 19MPG once on almost pure higway. I am planning on doing a comprehensive tune in a few months but I am going to get wideband as I dont have one yet.
What can be done to bump up the milage? I noticed the commanded AFR at ECT of 195+ is 12.4 but the 180degree commanded AFR is 12.0. Is it safe to change that?
If logs would help I can throw some up.