Thirsty Ibiza 6j TDI

[bombheads12]

Ok im getting a bit concerned my wifes 1.9TDI 105Bhp Ibiza 09 plate 65000 miles on the clock is getting very thirsty.
When i say thirsty even after a long run 250 miles its still only averaging 45 mpg and thats after cruising at 65-70mph. She norammly only drives 2miles per day to and from work and at weekends it gets to go a bit further lol around 35 miles in various driving conditions. i have regularly used Vmax to help keep the engine good and when i cant get that i add miller fuel additive to the tank.
It is regularly serviced by the local seat dealer and cam belts have been changed in the last 5,000 miles it runs quite well but occasionaly has a little burp like the engine revs will remain high 1250 rpm when at lights and then drop down to norm about 850rpm, if not blip the throttle and it drops.
It has only just been serviced in October but the fuel consumption has been on a steady decline for about 4 months
, i was thinking of getting it diagnosed but as people want £60 upwards to diagnose i think it is criminal
any ideas should i bite the bullet and get it diagnosed? and who by
p.s. I live in cornwall so its a bit short on specialists lol

 

[propane94]

I have the slightly newer 1.6 CR TDI engine in my Ibiza, and I have done a few runs to see what I get.

45 mpg is all right considering it's the old PD engine, I get 50-55 mpg in mine.

Vmax is a good idea but i'm not sure about the fuel additive, I have seen mixed opinions on them as they basically replace what goes bang meaning you will use fuel to get the same power.

With the 1250 rpm at a stop it sounds like your throttle pedal might be a bit sticky, hence when you press it it fixes it. However mine will idle at 900 rpm if the car is moving and 750 rpm at a stop, it will increase the idle between 1000 and 1250 depending on the DPF regen state.

With the decline firstly, check the little things like tyre pressure's, although trivial, a small drop will effect the mpg on a long run. Something else my be your driving style perhaps, you're pushing the pedal slightly more as time goes on, using slightly more fuel. Mine has cruise control which I find very consistent on the motorway.

I would check all angles before taking it somewhere and paying loads of money first, as for specialists, I have no idea as I'm in Hampshire.