Gallons per hour
 

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?

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.

FWIW:

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.

Are those numbers with the engine in drive or neutral?

6.0l GTO 6 spd GPH at warm idle is 1.1gph.
My saturn is .2 gph at 190d idle

Gph
 

Fully Warmed (Integra)

0.2 - 0.3 GPH - Neutral Idle (min. load)
0.4 GPH - Drive Idle
0.5 GPH - Drive, A/C, Idle or Neutral with cooling fan kick
0.6 - 0.7 GPH - Drive, full electrical load, A/C, Idle

RH77

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!

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.

Intrepid: 0.5 GPH idle when stopped, 0.7 GPH idle when in motion (that's why ICE off P&G rocks for this car).
Geo: 0.2 GPH whether stopped or in motion.

That's awesome that the Saturns only use 0.3 GPH. My mom's Cavalier uses 0.4 GPH at idle (2.2L).

My Honda Fit sees 0.2 to 0.3 gallons per hour (reporting 0.8 to 1.2 litres per hour).