V5 Fuel Economy Issue

[stuart_00000]

Hi chaps, wonder if anyone has any ideas on this one?

My Toledo V5 mk2 (AGZ 150bhp) is struggling to return any kind respectable MPG, at the moment, driving like an angel on mixed roads it only manages 22-23mpg!! Give it a bit of a prod and it will easily dip to 18mpg.
I had a Tolly a few years ago and that one returned 26-28mpg no matter how you drove it. This latest one has 110,000 miles (only 20,000 more than the last one when I got shot of it) and has been checked over by a SEAT mechanic and is perfectly sound.

Also, when driving in traffic (stop start and crawling) there is a strong fuelish smell that enters the cabin, almost as if it is over fueling.
It has a new MAF, temp sensor, crank speed sensor, has been de-chocked a few times and I regularly use redex fuel system treatment.
The car seams tops apart from the feul economy and it is starting to bug me.

I have my suspisions that the car may have been "tinkered with" by a previous owner, as it seems to keep up with things that it should not - a friends 330i, and it sounds like a V8!! but it all seems standard under the hood.

Could it be: faulty Lambda sensor? blocked/knackered injectors? fuel preasure regulator?

I am at a loss, any thoughts would be great.

Cheers.

 

[StuartL]

Could have been chipped, perhaps there's an automatic choke problem or as you say lambda sensor issue. Anyone with VAGCom can get the fault codes for these (including your local Seat dealer) and give you some areas of investigation.

Have you checked the obvious and checked that the fuel line itself isn't leaking?

 

[stuart_00000]

There is no physical leakage of fuel anywhere.

VAGCom has been previously done, only fault codes were for the Temp and crank speed sensor. Both have since been replaced and car has no further faults logged.

 

[GrayT]

I would have said MAF first but you've changed it. Again you say you've checked but often leaks occur if the fuel filter not clipped in properly. The smell and poor economy would suggest a leak, especially if you are not noticing a difference in how the car drives ie no pinking, etc.

There is not much to do to a V5 to improve a performance beyond a remap. This would not be noticeable under the bonnet. I have one but it does not give as startling an improvement as you suggest - it adds about 15 bhp (20 tops). Though it's satisfactory enough.

 

[superkully]

Have you checked/replaced the air filter & piping?

 

[stuart_00000]

air filter is new, not sure about pipework!
Many of the vacume/pressure hoses in the engine bay are soft and some may be weeping a little.