Quick MPG question

[Zeek19]

Hey guys, I've finally got my poor car engine running pretty well(I posted a long time ago with numerous engine noises...timing/ignition coil we're bad...) anyways now that things are running smoothly I have found that I get terrible highway mileage..

I have a OBD Bluetooth dongle hooked up so I can read the stats off it with my phone and from what I see it gets about 25-26mpg at 70~mph or so.. To me that's pretty bad. Also, if most of my driving is highway instead of in the city, I still overall only get maybe 27mpg if I'm lucky.

Anyways, I have a 2007 aveo, manual transmission, 15inch tires, yes I've factored in the speedo being off, I have a gps hooked up as well as a speedo app on my phone and such to make sure it's accurate.

Another thing I noticed is that at 70~mph I am at around 3,300rpms maybe 3,400, but it's pretty high up there and the car is loud as heck(like it's really bogged down). However, if I push it to like 75-80, the engine quiets down, but the mpgs def aren't any better.

A side note, I do have cruise control wired in and it's not the most perfect wiring job in the world, but I wouldn't think it would cause any issue? (I followed a guide on here when I installed it) Oh and I found an article saying there was a "bypass valve" for the intake that is supposed to kick in at "high rpms", what "valve" are they talking about?

[Pickles]

Your mpgs sound normal to me... drop the speed down to 60-65 and see them go up. although this is a boring way to drive

[wylee]

I got about 28 on the highway in heavy rain with the AC on. Yes, rain made quite a difference.

[NYChevoo]

My 04 sedan typically got 30mpg hwy around 65mph. I had NGK BKR6EIX laser iridium plugs, Magnacore 8.5mm wires and a K & N drop in air filter. The Aveo felt slightly peppier and got decent mileage.