2 questions

[farmer70]

Is there a way to search past posts? I’m sure my main question has been covered before. Realistically what kind of MPG can I expect out of a Peterbilt 389 flat top pulling a hopper weighing 80,000 everywhere? It’s got an ISX 500 13 speed and 3.25 rears. I was in the wind yesterday and my mileage was horrible. I’ve got a lot of bad habits I know. I’d be ok with 5.5-6 how difficult is this. I had a daycab Freightliner with a C12 cat and a big gap between the trailer and cab. I think my mileage was better. Will the EGR tune up help a bunch? I pulled the imap sensor it had a little buildup. The engine is a 16 2350. Will change the Delta sensor. On flat ground which I’m on a lot it seems like if I set the cruise at 62 in 12th gear I’m at 1400 RPM seems like a good setting. What is recommended? I know my aerodynamics are crap but what’s attainable realistically?