Mpg Guage

[Parthiban]

While out this afternoon, I noticed my mpg guage doing some weird things. I was driving down a hill at about 30mph, foot completely off the pedals and instead of sitting right at the top at 80mpg, it was pointing at 60. Weird I thought, but then noticed I was actually in 3rd gear so not sure if that was the reason.

Then even stranger, touched on the brakes to slow down and the mpg dropped to 50

Is that normal behaviour or is my guage just having an off day

[spikes]

While out this afternoon, I noticed my mpg guage doing some weird things. I was driving down a hill at about 30mph, foot completely off the pedals and instead of sitting right at the top at 80mpg, it was pointing at 60. Weird I thought, but then noticed I was actually in 3rd gear so not sure if that was the reason.

Then even stranger, touched on the brakes to slow down and the mpg dropped to 50

Is that normal behaviour or is my guage just having an off day

does seem a bit strange, will try mine 2morro as i dont normally take much notice of it :)

[Purvesh]

Mate, mine does this at times aswell.

I think it works off air pressure through a hose or something, maybe Matt can advise further...

[Jack300]

I think it works off the engine management computer. I've converted my 3ltr SX to run on LPG and the mpg guage still reads as though the car is using petrol - so, lets assume it's checking wheel revolution vs throttle position and which gear you are in and coming up with some average calculation... It's certainly not measuring fuel used...

Good luck

jack