Right I'm a bit confused with my trip computer. I wanna find out what my MPG consuption is. When I set it to Average MPG, it goes from 42.2 to 42.3 MPG, both in the city and on the motorway. When I set it to Inst. Consuption, I just goes all over the place between 35 and 80 MPG. So I'm a bit confused, how do I actually find out what my true MPG is.

Also, I just recently drove to London and back 70MPH all the, 180 miles round trip and spent £30 diesel.less than what I spent on a 1.6 vauxhall astra last time round. Should I be worried about my consuption? What could it be?

I have an error message saying check glow plugs. And the engine sign is has been permenantly on for around for weeks. Got a code from the computer scan saying EGR Valve Fault, and Undocumented c

Hi, I need to make sense out of my trip computer. When I set it to average mpg consuption, it goes from 42.2 to 42.3 mpg, both in the city and on the motorway. When I set it to inst. Mpg consuption it goes all over the place from 30 to 80mpg. I wanna know what my car is avereging so which one is it?

Also today I drove to london and back 70mph all the way, 180 miles round trip and I spent £30 diesel, the same I spent on a 1.6 vauxhall astra petrol last time round. Should I be worried about this? And what could be the cause?

I have a warning message when I start up the car which then goes away saying check glow plugs, and the engine light has been on for around 4 weeks. When my friend plugged his ecu scan the error message that came up was Faulty EGR valve, and undocumented code. Could this be the cause to my problems?
I have lost a lot of power to the car, car doesn't develop until I go past the 2.5rpm mark in all gears, and there's some sort of hesitation/bump when I change from 1st to second, whereas before soon as I put my foot down it was gone.

Fiat Stilo JTD 1.9 multijet 120

Thanks

Your average MPG is the fuel consumption over a certain distance (not sure how much exactly), the instantanious consumption is your MPG at that exact moment - when you put your foot to the floor it will go right down to maybe 20mpg or so but if you take your foot right off it will go up to maybe 70 - 80. It's probably best used on motorway journeys when you barely make any changes to your speed/throttle position.

I'm not all that familiar with diesels but if you have a glow plug fault it's best to just get them changed. As for the EGR fault, you should try cleaning the EGR valve first as a dirty one can cause poor running of the engine. If that doesn't help then you probably have to replace it.

MarkThompson4 said:

Your average MPG is the fuel consumption over a certain distance (not sure how much exactly), the instantanious consumption is your MPG at that exact moment - when you put your foot to the floor it will go right down to maybe 20mpg or so but if you take your foot right off it will go up to maybe 70 - 80. It's probably best used on motorway journeys when you barely make any changes to your speed/throttle position.

I'm not all that familiar with diesels but if you have a glow plug fault it's best to just get them changed. As for the EGR fault, you should try cleaning the EGR valve first as a dirty one can cause poor running of the engine. If that doesn't help then you probably have to replace it.

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Thanks for the reply.
New plugs came through the post today, and getting the valve cleanead tomorrow. Hopefully that will sort it.