Hey folks my tddi focus is runnin bad no power at all mechanic put it onto the computer and there was no error codes although fuelling jumped between 22 and 60 he said could be anything from injector pump to cat. Would it mayb be the egr valve??? Bit of smoke and odd chug especially on a hill at full throttle!! Any help much appreciated.

cleaning the egr would be a good place to start, will not cost anything but time and some cleaning agent.