My 2000 ford focus 1.8 petrol with 140K on clock has been running !Removed! and is completely gutless and struggles to get up hills at motorway speeds etc an its got every1 completely baffled as to why.. Does anyone think an engine carbon clean would make any difference to it?? Seen a company that comes to your house for £99 so thinking of giving it ago.. 

Why not start with a compression test?

Does the car have a full Service History?

are the tyre pressures correct?

Could the brakes be binding?

It's your car so try what you think but at 140k miles you may not like the result of decarbonising, smarter I think to run through the basics first.

I should imagine it would make a huge difference 16 years and 140k miles later giving it a clean will likely do wonders, have a look at Terraclean.

Its got no service history but was serviced 10 months ago by my dad an has only done 3500 miles since then.. A couple of weeks ago, i put petrol in an then it refused to start, got it towed home an was checking thru an found the fuel pump fuse had  blown so replaced it an it ran abit better an hasnt done it again since but drove dartford on saturday and i had to work the gearbox an engine really hard to be able to get anywhere.. once at 80/85mph it ran ok up til i hit a hill then only way to get it to stay at speed is drop it into 3rd.. drop it into 4th an it still wouldnt make any difference an no power.. 

The brakes an tyre pressures are perfectly fine.. tyre pressures were checked before i left.. 

reminds me of a clogged fuel filter issue i had. could be air in the fuel filter?

Iv got a fuel filter here ready to go on soon as iv got oil an filter, coil an new leads to give it all a change.. it was only serviced (oil,oil filter, air filter an spark plugs) by my dad 12months ago (3500miles ago) its not been used much tbh due to ill health which prob hasnt helped i guess..