I just took a trip from chicago to right around dallas, tx in my 05 Redline. My average mpg at 72-75 was 27.5 and at 65 i got 31.4. Driving just around town I get 26.4 average. Is this normal? I was expecting low 30s, got a homemade shortram intake right now and thats it.

This is normal. 75 is getting up there.

55-60 is the sweet spot for mileage. What car do you have? I hope a 2.0 because you would be low for a 2.2L

with my 2.4...
I get about 29mpg at 80mph cruising up to DC

Sounds about right...maybe a tiny bit low, but that could have been caused by a headwind, uphill grade, low tires, etc. A little over 30-35 at 65 mph is about right for a 2.0, though.

its an 05 redline so its a 2.0. Only thing that confuses me is the 26mpg stop and go traffic and 27 on the highway.

i get
38mpg at 55mph
36mpg at 65mph
32mpg at 75mph

check your tires and see if theyre at the right psi.