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I forgot, there was a 25 mph winds with 40 mph wind gusts blowing in my direction of travel. It really really messed up my numbers, will do another one again. the tank of A-B-A was 105 miles, plus 15 miles on all 8 cylinders. Going with the wind the truck drove alright, going into the wind it was dangerously slow, I could not get past 60ph no matter what I tried, even rolling onto the highway was painfully slow, borderline dangerous: I need to have a switch to have all cylinders available on demand.
Most of the return trip was done in 3rd gear, engine close to 3000 rpm, a bit much for a v8. On the last half of the return trip I got off the freeway and drove some back roads, at 55 I needed significantly less throttle to maintain speed.
I noticed a similar phenomena on my jeep when I had the scan gauge plugged in, as I posted this on another forum:
I have been monitoring the 4.0 for about 6000 km with my scan gauge II. Well worth it. You can actually monitor the engine real time, all the sensors 4 at a time and fuel economy. The jeep has a funny quirk I noticed when monitoring the throttle position and fuel economy. At set throttle pressure the jeep will hit rpm humps that it cannot climb over without slight throttle increase, but will yield unproportional rpm increase. For example, at 105 on the clock, 100 actual speed at 17 units of throttle the jeep cannot accelerate and will cruise at 19mpg. If I increase throttle speed increase but mileage stays steady. However if I decelearate slightly mileage jumps up 1-2 mpg. I noticed 3 of these rpm humps at highway driving, as if the jeep lacks the torque to accelerate but at little more rpm on a different part of the torque curve if descending into it. Make sense?
Best explanation I can give is like lifting weights. Takes less power to hold than to lift. If faster speed is used to lift more weight can be lifted. Less work to quickly lift a weight and lower to set height than to lift up to that
This effect was very noticeable with the v8 running on 4 cylinders
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