try slipping it into neutral while coasting down hill - you'll see the RPM's drop to below 1k during that time, saving you gas. it can almost make up for the gas you use going up hill. the honda's and toyota's i've owned had no problem doing this on a regular basis - the auto tranny can slip between N and D with ease - and won't slip into R unless you press the button. just don't forget you're in neutral, and hit the gas, up the rev's, then slip back in gear - that would be bad. only put in gear when RPM is below 1k. inevitabely you'll forget, hit the gas, hear the rev's - then you must wait until the engine calms down before you slip back in gear.
a 4cyl will use less gas than a 6cyl in almost every case, even uphill. even though the revs on a 6cyl may be lower, you have 150% fuel usage at all times. my VVT-i4 2002 camry is almost as peppy as my accord and it is our travelling car. no problem going up hills fully loaded with the family. that said, i hit 6k RPM on my Accord very often and it does so effortlessly, the Camry seems to not like that as much. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif