I have a 1995 Honda Civic Auto 1.6L VTEC. What speed would give me the best mileage? I've heard anywhere from 45-55 as typical and some rare exceptions at 65. At 65, I get 2500 RPM, 60 MPH = 2400 RPM, 55 MPH = 2200 RPM, 50 MPH = 2000 RPM. I've been slowly accelerating and noticed if you push on the gas pedal too hard, the car will shift up to 3000 RPM (probably when VTEC kicks in). Likewise, less than 2000 RPM doesn't seem ideal if you step on the gas pedal too slowly. I've been trying to keep it between 2000-2500 RPM. Since the car can't use a ScanGauge, I've had to guess at what works.
Keep the rpm low. Learn the car's shift points. If it shifts at 45 into top gear, get it up to 46 or so and let up on the gas. It'll shift, and then you can get back on it in the higher gear. "fake-shift"
I use a fairly heavy acceleration rate, but my manual will allow that without downshifting. Since you're driving an auto, just keep it as low as possible. I'd say below 2,500 while accelerating.
For cruising, the lowest speed that will hold top gear will give you the best numbers. Don't give it enough gas to shift down, but just a touch less than that.
I've done 34 mpg in my Odyssey (V6 auto) using these ideas, along with neutral-coasting. It's rated 21 combined.
I've been slowly accelerating and noticed if you push on the gas pedal too hard, the car will shift up to 3000 RPM (probably when VTEC kicks in).
No, VTEC kicks in a 5000 rpm, give or take 100. The transmission is either downshifting to a lower gear, or the lockup clutch in the torque converter is releasing. Neither are good for fuel economy.
I can't say exactly what will give you the best fuel economy... I'm using the same engine (D16Z6) in my CRX, but with the previous generation automatic transmission. In my case, the torque converter won't lock up below about 40 MPH, and even then it's highly dependent on how much throttle is applied. I've gotten pretty good numbers in the 55-65 mph range, but the aerodynamics of a CRX and Civic Sedan/Coupe could be quite different.