car economy question

[Wideboy]

lately my car has been thirsty and today i think its been to thirsty

today I've been to Exeter and back (about 220 miles). The 1st 20miles of it were motorway and dual carriageway and my fuel dropped a fair bit so worked out the MPG in my head and it had done roughly between 22-25 MPG, that was sat at 70 with cruise control most of the way..........not odd you may think but its a 1.4

the rest of the journey it was fine and did what it usually does

i can't work out why its drinking so much, it has no performance mods, serviced regularly, not leaking, not playing up in anyway and I'm driving with a feather boot on ............. its does need a new back box though as the current one is rusted and all loose inside, but no wholes and still passed the MOT

could that cause low MPG? or what else could be up?

Originally Posted by Wideboy

could that cause low MPG?

tyre pressure?

[Luckypants]

You not mentioned tyre pressures. One of my daughters things used to be to phone and moan her car using lots of fuel and so must be broken... I'd say have you checked the tyre pressures?.... Silence....

Hers was a 1.4 and would do low 20s when her tyres were flat.

were you parked on a slope at the start of the journey, my car has a delay on the sensor to equaite for bumps etc so it may have started atrificially high.

Also on a 200 mile trip in a volvo 2.0 Turbo diesel I did a test - the cruise control at 75 averaged 45 mpg - I averaged . . . . . . 60!! and according to the computer the average speed was actually higher!

[Wideboy]

aha tyre pressure could be it , i had a feeling my compressor gauge was out a few weeks back

[Skip]

Tyre pressures and I would check the air filter - see how dirty it is - that wont help.

[maviczap]

Originally Posted by Skip

Tyre pressures and I would check the air filter - see how dirty it is - that wont help.

Aye, who did the servicing, you or another (in)competent mechanic?

If a garage did it, then don't rely on them adjusting any fuel air/mix for best fuel economy. They'll just change fluids, filters and grease bits if you're lucky.

If you did it, then change the air filter and get the engine tuned. I had one of those mobile tuning guys come round and tune up my Cav. Needs doing again, although it hasn't failed on the emmissions at MOT since I had it tuned, and that was years ago.

[Wideboy]

i did alot of work on it about 300 miles ago done by me, oil, filters, plugs, belts, coolant, water pump and brakes but it was like it before. i did have a ECU fault a few months back but was plugged in and turned out to be a loose connection on it

[maviczap]

[QUOTE=maviczap;2028123]Aye, who did the servicing, you or another (in)competent mechanic?QUOTE]

I'm not suggesting you are an incompetent mechanic by the way

Having taken various cars to dealerships and hearing a work colleagues tales about when he worked for a Ford dealer, I wouldn't take my car to a main dealership.

I prefer my local independant these days. Mostly on price, but at least they don't try and rob you blind for work you don't need doing, or charge you the earth for parts for the work you don't need doing.

Step forward Vauxhall main dealers

[Wideboy]

i've only ever taken it to a dealer with a computer fault, but even then i watched them .......... hate garages