I read the manual to find out the recemended shift points on my 07 civic and it was

1st-2nd 15mph
2nd-3rd 27mph
3rd-4th 39mph
4th-5th 53mph

Now today driving to work I was gonna try driving and only shifting at these shift points since I usually shift a bit earlier in the city and going all out on the freeway. SO I was wondering if traffic is making me go around 25 mph should I keep driving in 2nd gear or shift into 3rd? Normally through the city I shift really early like into 3rd around 22mph or 2500 rpm.

 

play around with i to see which way gives you better milage but a general rule of thumb now notice I say general is the higher the rpms the more gas is being used but in all reality you have to factor in the load that is being put on the car and such.

 

You mean like if the rpm gets too low in a higher gear then it could be struggling to keep up that speed compared to a lower gear at higher rpm keeping the speed easily?

 

Yes if you are too low of an RPM for the gear, trying to get power can be difficult, if not non-exsistent, so shifting up too early will mean you cannot slam your foot down expecting to take off. So just read the road and traffic for how you should be driving, ie a hill coming up, you don't wanna upshift yet, congested traffic but flowing, upshifting might not hurt, etc.