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[sounds2k]

Hi folks,

I'm concerned about the economy (or lack thereof) of my barge. Admittedly it's a 3.2V6 auto which is never going to be economical per se - however (as an example) yesterday I put in £20's worth when the range was showing about 7 miles left, drove 60 miles of which about 45 was on a return trip which included about 80% motorway driving, the remainder was the usual urban stuff but not stop/start. It then said range was 29 miles. This would put the range of that £20's worth at approx. 82 miles - working out to an average of 17.85 MPG - which strikes me as a bit juicy !!!

I tried resetting the trip computer whilst on the motorway on the way back recently, it said about 25-26 MPG whilst remaining on the motorway, but once off it dropped down to about 23MPG by the end of the journey.

Is this normal as such - I don't expect miracles round down but on a run it seems to be a bit thirsty?

If not, where should I start looking? I was considering changing all the inlet manifold, throttle body and breather "top hat" seals ...

[Dazzler]

The trip comp sounds about right for that car.

[Darth Loo-knee]

Seems about right mate.... I always think £20 doesn't go far :-?

[bob.dent]

I tried resetting the trip computer whilst on the motorway on the way back recently, it said about 25-26 MPG whilst remaining on the motorway, but once off it dropped down to about 23MPG by the end of the journey.

This seems to be pretty normal for a 3.2 auto estate - I've got the same lump in mine and normally get around 21- 22mpg urban/town and between 24-26mpg motorways, and thats with a heavy right foot

[Kevin Wood]

It sounds a little more thirsty than mine. Mine takes about 65 quid's worth when I fill up and it'll generally have done 330 - 400 miles by that time. I make that 24.5 - 30 MPG, and it pretty much agrees with the trip computer.  That's 100 miles on 20 quid at the worst case.

However, mine (thankfully) doesn't get much real urban driving. It really drinks it doing stop-start driving and short journeys. My normal commute is turning out of my street, a mile or two of 40 MPH max urban driving then I'm on single carriageway "A" roads for most of the journey (20 miles). Maybe 5 miles of stop-start at the other end. Doing that commute it averages about 27 MPG. Trip computer appears to be accurate. Maybe about 1 MPG optimistic. Driving style is normally fairly relaxed, with the odd wicked streak when I get the opportunity.

On the motorway the trip computer reckons about 32-33 MPG at a constant 70-75. Probably down to 30 MPG at 80. On a recent trip round a fairly congested M25 (so speeds a bit lower) the average finished up at 36 MPG.   That surprised me because there was quite a bit of stopping and starting. Then again, the cruising, such as it was, was only 50-65 MPH.

If I reset the computer on the motorway and let the average build up again, if it's significantly under 30 I'm either driving up a hill or like a hooligan (sometimes both).

I'd do a few tankfulls of brimming the tank, resetting the mileage and then calculating the consumption at the next fill-up rather than relying on the MID. It could just be that the MID calibration is off for some reason (wheels / tyres the original size?).

Other than that air leaks are a possibility I guess. Any fault codes stored? Air filter, plugs, fuel filter, etc. in good condition?

Does it otherwise run perfectly? No idle speed control issues, misfires, hesitation etc?

Kevin

[Kevin Wood]

... of course, mine's a saloon rather than an estate. I wonder how much difference that makes?

Kevin

[VXL V6]

Got the same engine and box in mine, my work journeys average about 23 - 25 mpg (there's a nice hill to roll down in the morning but you use all the fuel getting back up it on the return!).

When I get to give it a decent motorway run I reset the computer and average about 32 - 34.

Edit: Kevin, looks like ours seem to be about the same consumption then.

[sounds2k]

hmmm ... maybe that's just how it is then!!!

I changed the spark plugs and all filters (including fuel) soon after purchase which was about 5 months ago now. As it's a 2002 (52-plate) model the paperclip test won't work. But the engine management light comes on and goes off as expected at startup and there's no noticeable idling or other issues.

It's just that having bought the Saab 9000 - which is an almost identical power output and a similar weight - it's not only noticeably faster but on the return trip from Plymouth where it was collected (a 250 mile trip each way), the omega used £10 more petrol with the occasional bout of thrashing of both ... which to me is a significant difference ...

[TheBoy]

My 3.0 auto, I expect high 20s/low 30s on a motorway run at a constant 80....

[Paul M]

Sounds about right, I average 24-26 MPG in mine driven quite hard, but that includes a fair bit of motorway and mine is a 3.0 manual. I don't expect much difference in economy between the 3.0 and 3.2 -- the small increase in displacement will be offset by efficiency improvements. Having a manual gearbox would definitely help though.

[Jimbob]

Low 20's round town, High / low 30's on a good run.
If you haven't bung a bottle of Forte Gas additive in with 1/2 - 2/3 tank of petrol, give it a good clean, may improve it slightly.
Tend to do that in ours about the same frequency as oil changes - 5000m tops.

[Markie]

sounds about right to me - £20 gets 100 in local driving for me...

[Lordmpl]

Mines only a 2ltr, but i get about 160 miles for £20

[TheBoy]

Mines only a 2ltr, but i get about 160 miles for £20

Tractor I get about 300m for £30...

...trouble is, it uses as much coolant as it does diesel...

[Jimbob]

Mines only a 2ltr, but i get about 160 miles for £20

Tractor I get about 300m for £30...

...trouble is, it uses as much coolant as it does diesel...

we should have got together for a bulk discount!