A bit history (always helps I guess)
Earlier this year the coil pack went on my 2001 1.8 Zetec Focus, I got the coil pack replaced and all seemed well for a few days and then the Engine Warning light came on again, about the same time I noticed the car idles unevenly.
The Error code was 'P0420' which I gather is down to a Lambda sensor (which I promptly replaced) and made no difference the error code keeps coming up the engine idles unevenly and increasingly I've noticed a distinct lack of power and in fact a loss of power when climbing a hill or carrying a car full of passengers.
Planting my foot to the floor also results in a loss of power, easing off again actually helps.
Recently I've noticed the car won't go over 4100rpm, often from 3000+rpm the car judders as if it's running out of fuel.
The knock on effect is around the doors the car is fine, but on a motorway it's a pain not being able to sustain 70mph as soon as it sees a hill.
I've had the spark plugs changed to platinum tipped ones (no change)
I've had the Air and Fuel Filters changed (no change)
And I've had an assortment of minor things checked out all to no avail.
The Engine Warning light still comes back (P0420) and I've sort of come to the conclusion when the Coil Pack went it took out the Cat.
The reason I'm asking, is it likely to be the Cat that's causing my power problems? any thoughts and opinions more than welcome, I'm not a mechanic but fortunately a good friend of mine is, I just prefer to do a bit homework myself before wasting his time chasing ghosts.