1.6 Focus 'fuel Starved'

Hi evryone out there in helpful Focus Forum land!

I joined up today (at last) although, it's not for me, it's the Mrs that has the Focus, I'm cruising motorways in a Vectra (I'm cowering while you all spit in my direction!).

I've been meaning to join up here for a while as I do like her Focus and while she's thinking of changing this year (to another one) I'd like to get this one properly up to scratch and being a bit more of a nicer car than Ford were able to muster in 2003!

Anyway, we have a long running issue with the running of the car.

It's a 2003 (53) 1.6 LX (like so many out there!) but it runs rough as, well, you know what, from the last quarter of the ank, when driving hard, doing quick gear changes, or cornering 'excitidly'.

It will cut out after much spluttering when going round a roundabout (on a quarter tank) and even when the tank is full, you can't run the rev's up and change gear quick as when you let the clutch back up, your foot can be brushing the tarmac and it's won't go, there's a delay, almost like turbo lag!

I refuse to drive it because of these factors, so we go everywhere in mine and I've had enough of her complaining, so want to get this sorted if we can, or find out if it's gonna be so much easier to just get rid and buy again!

I saw something about 2 years ago suggesting the possibility of a compression problem in one of the cylinders or a possible fuel pump problem, but haven't been able to find out much more since.

The engine light is perm. on on the dash, but not had any codes read as yet

Any help that anyone can provide will be most useful and appreciated

I'm no novice with cars, I tinker and fix most things that aren't huge and I owned a Laguna dci for a year, so am not adverse to problems!

Thanks

Russell