Hello I just bought a scan guage and I love it, and my 2000 Daewoo Leganza automatic 2.2 liter is showing .5 (sometimes .4) GPH At a warm idle. By comparison, The Ford ZX2 (2.0 liter, variable cam) gets 0.2 GPH and a Chevy Tahoe 5.3 liter gets .6-.8.
The Daewoo drives fine, 30+ mpg at any steady speed, at long as 4th gear is enguaged. Its when I am coasting to a stop and idling, that really slaughters my average MPG, with that .5 GPH
Whats normal GPH at idle for you guys?
85 Chevrolet. 30 MPG or bust!
My 1.9L DOHC Saturn SL2 warm idles @0.3 GPH @830-840RPM. Could be 0.349 for all I know since the SG shows to just one decimal place to tenths. Since your car idles at 0.5 GPH, sometimes 0.4 GPH, it might be teetering on the edge of 0.449 to 5.0. Not sure how SG rounds off the 0.01 decimal place.
I just ran some calcs and came up with between 71-350 mpg for the three vehicles in the OP, for neutral costing speeds between 50-70 mph.
I wanted to post the tabular results here but the columns wouldn't line up. If you can make a halfway informed guess at your own car's idle consumption based on the information in this thread then you can calc the mpg at different coast speeds.
Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.
Scion xB 1.5L
0.2gph at 850rpm usually until you stop for a minute then it calms down and drops to 0.1gph at 650rpm and sometimes after I stop for a few minutes then take off again I can get it back down to 0.1gph while coasting and then I really rack up some MPG on a trip - was not happening today however for some reason. What's interesting is when you change to Liters . . . very interesting.
Still did ok getting somecountry road work in 53.4mpg return trip 49.1mpg today several stops 46.3mpg tank average WOO WOO!
Are those numbers with the engine in drive or neutral?
Not sure if this was directed to me or OP, but my car idles at 0.3 GPH, "parked" in neutral, minimal engine load (even with clutch pedal down to eliminate parasitic loading through the clutch disc and tranmission input shaft). The lowest GPH I've seen fully warmed up (181F) is 0.3 GPH. From reading the other replies, another plus for the SOHC Saturns vs my DOHC... lower idle gas consumption.
I guess I do need to replace my stock 185F thermostat with a 192F to eek out an MPG or 2.