Hi, new here! Anyone able to help me out... Sometimes, after going around 50mph +, changing down gears when clutch in I get really high revs, around 4,000. After this I could come to a stop, hand brake on. Clutch in - revs high, clutch off - normal. When it's doing this before I put clutch in it climbs speed a little, and brakes seem harder to press and give little effect.

Any ideas?? Much appreciated. Cheers

Hi - you don't say how old your Focus is or whether it is a petrol or diesel

Faulty throttle pedal - it could be the potentiometer or connections in the throttle pedal giving the ECU a false reading

Or burst leaking brake servo or diaphram - if the diaphram in the brake servo is burst or split it can mean you have to press the pedal very hard to get the same amount of braking, ditto the servo hoses -

this can also cause a leak in the intake which can sometimes cause fast running

Thanks for the response. Ah yes it's a petrol, 2001 model. Someone mentioned resetting ECU which I did with no effect. Is there something I can look at myself do you think? Thanks again

Yes, could be the diaphram or associated pipes- the brake servo uses the suction from the inlet manifold to boost the brake - its diferent on a turbo (petrol or diesel) and the diapram/ pipes are more likely to split on an older car (yours is 11 years old now)

If its the diaphram/ pipes, the reason the revs rise is because the engine is drawing extra air through the splits

See if you can hear and hissing/ growling noises that were not there before - have someone rev the engine up/ press the brake as you stand over the engine (bonnet open!) - check specially around the master cylinder and associated hoses - it may be only in certain circumstances it happens - you could also disconnect the brake servo vaccum hose (with the car stationary) to see what happens (do the revs rise?) and of course do a visual inspection of the hoses

Great, thanks a lot for that. I'll do this in the morning and see what I can find. Cheers