After a homemade CAI, Resonator Delete and IAT mod i was able to get 18.9 MPG on a 600 mile trip. Is this good or bad?

Cruise Control Set at 75mph.

 

Thats pretty good. When gas prices was over $4/gal a couple years ago, I really paid attention to my driving and was able to get my MPG to about 20 MPGs. Helped that my commute was always highway driving and I never let my RPMs get over 2000.

 

did you hand calculate or just use that overhead for the 18.9?

the overhead has shown to be pretty inaccurate. Mine says 12.1 and I hope its off big time

 

Better yet, what engine are we talking about here? 3.7? 4.7? 5.7?

 

5.7L Quad Cab

 

My manual calculation puts me at 18.3 I wonder if i would've set the cruise control at 70 if i would've gotten better mileage.

 

Gotta be a 2wd. Why would you think 18mpg is bad?

Clearly you already know that is good, especially since you said "I was ABLE to get"!
Heck, my explorer gets worse mileage than my Ram does weighing in 1500lbs lighter, narrower tires, lower to the ground and has 180hp less..Ohh and it's a v6 too..l,ao It's pretty pathetic. Good thing it's only my school beater.

 

I honestly had no idea what the average highway mpg for these trucks was. Last time i took the same trip in my dad's Malibu we got there and back on almost a single tank doing 32mpg!

 

Not bad for 75mph. I find for my truck 65mph on the cruise can net me upwards of 19, and even 20+mpg if the wind is at my back and I draft a semi going the same speed. However, I dont use my truck a lot as My metro nets 60mpg on the highway with cruise set to 70 and even more if I am in enough of a suicidal mood to draft. That car is so light that If I get in the right spot the draft of a semi will almost pull it along with it.