UK Car Repair Questions? Ask a Mechanic for Answers ASAP
I am sorry that you have not been helped yet. I just came online and saw your question
Ok, the first thing we need to check for is a partially restricted catalytic converter. A shop can test the back pressure, or you can remove the O2 sensor at the exhaust manifold and take on a test drive and see if power is restored going up a hill. If it is, replace the converter
If no difference, let me know and we will go from there
Ok, that eliminates the converter as the culprit
Lets make sure the intake passages, fuel injectors and valves are carbon free.
You will need a can of SeaFoam cleaner, a funnel and a helper.Disconnect the large vacuum hose at the brake booster(this goes directly to intake manifold). Have helper crank engine and every few seconds, goose the gas pedal to keep engine from stalling. Stick funnel in end of disconnect vacuum hose and slowly pour contents of Seafoam into funnel.( It will smoke white out the exhaust when doing this, which is normal for this procedure.)Once done, reconnect vacuum hose and drive for about 5 miles at hwy speeds to finish cleaning out carbon.the above will clean carbon from valves, intake manifold and injectors.
Here in the US, it is sold for about $8 a can at parts stores nationwide. I would imagine it is available in the UK as well, but if not, you can order it from RockAuto.com
Most shops charge around $120 US dollars to do this service, referred to as a direct induction cleaning
Ok, sounds good