1997 2.7L 4wd - fuel injector cut off when above idle?

I'm wondering if on these 1st gens the injectors cut off, or go to their absolute minimum, when the engine speed is above idle. I'm thinking of fuel consumption in a long downhill slope, if coasting in neutral is using less or more fuel than foot off the accelerator, "coasting" in gear. I'm aware of safety concerns about being in N that long, and am not talking about taking big curves or anything. Just asking if anyone knows which state is using more fuel. I have read that "modern" vehicles may actually use more fuel if coasting in N depending on the rpms.

 

When coasting in N the injectors are still spitting fuel to keep the engine idiling. When letting off the gas and coasting in gear, the injectors are NOT spitting fuel. But a coast in gear doesn't last long due to engine compression...

 

I was noticing that today going down one of the many grades I traverse each day. In gear the truck wants to slow down (unless a fairly steep grade), whereas in N it is a little more inclined to keep the speed up. In gear my rpm is a tad over 2k, in N a tab under 1k, so I figure it is sipping fuel while in N. The data nerd in me wants to splice into the fuel injector power lines and real time capture the voltage readings, align with gear selection and data on the amount of fuel the injector sprays out dependent on the voltage, and come up with a chart. I am not sure if Techstream is capturing injector voltage on this year - I'll have to check that out. I think it does on my '09 Camry.

 

So long as your foot is not pushing on the pedal, the throttle body is 'AT IDLE' (fuel injectors ALMOST completely shut off). I have an Ultragauge and always have the instantaneous MPG on the display . When going down hill at 60 mph (with foot completely off the gas pedal), I have seen up to 200 mpg on the display. Being in gear or in neutral made very little difference.

YMMV

 

My ScanGauge II would do the same, but I could never get the fuel cutoff value dialed in right, so I tended to get all 9's for the MPG when coasting. I've read these type gauges are not accurate in that regard anyway based on the way they derive the mileage. I've been doing fillup math to gauge my values. I have been wondering if my fantastic mileage of 23-25 mpg has been more due to my tendency to coast in N down these long grades or due to filling up with Chevron gas exclusively for months now, thus cleaning up the system.