I just recently bought a 2007 mazda6 i and this is my firsttime using a manual transmissionas well asfirst time owning a four cylinder. I noticed that i'm at a little over 3000 rpms at 65 mph in 5th gear on the highway (Which i figure must be an efficient rpm consider that is a pretty average speed for highway driving and i'm inthe lastgear). I have been driving at about 2000 rpms in the citydoing about 35 to 40mph in 4th gear and it doesn't sound like it's bogging. So my question is,is it most efficienttobe cruzing a 3000rpms all around (whether in 1st gear or 5th) or is it better to be at lower rpmsat slower mph.