Like you said, up to 4100 it is throttle position dependent, hence the 4000 part of my explanation. Then the 'up to 5000' part is based on better to have a little more power at light throttle then to floor it at low throttle explanation about fuel economy. Probably should have been a little clearer, but I didn't expect the vultures from the rafters to pounce that quickly.
Perfect example was a rental car I had years ago, a dodge something or other ATX. To get anywhere with it faster than a snails pace I had to floor it until it got up to 40mph where I could finally let off, it was really that slow. THe fuel economy was horrendous and it was a 4 cyl atx! I had to gas up every two days since it was a small tank too. So what I did was turn off the ac and lightly accelerate. It was very slow, like Model T slow but at least the gas mileage improved.
I ended up with better gas mileage in the Contour by using light throttle even at higher rpm, up to a point.
I found that anything 5000 rpm and over would noticeably use more fuel than up to it.
So I'm talking as a three new contour owner over 10 years, my original 95SE that I traded for the 98 SVT in 97 when it came out and of course that one was bought back by Ford because of so many little problems and I got a 99 SVT that has been great. So I've owned an example of each V6 engine setup except for returnless style and I this stuff holds true IMO.
