any one out there able to shed a little light on a problem i have with my 2003 tdci 1.8 focus...it failed to start a couple of months ago fit another pump symptoms still the same .got the injectors checked and they were shot .got them reconditioned fit them and car fired up streight away.drove car and it cut out.re-started no problem,runs ok.once left and re started it runs ok then goes lumpy and struggles to rev in lower rev band then will cut out ?????but will re start and be ok...changed the meatering valve in the pump as someone said it could be that and its still the same...its bringing up error code p0423...has anyone encountered this before and what could it be?????any advice would be greatful

 

P0423 Heated Catalyst Efficiency Below Threshold (Bank 1)

it could be an oxygen sensor is not reading properly or the temperature sensor, or could be the cat or the exhaust leaking, you will have to eliminate the easy ones first then get the sensors tested.
adam

 

guys is there anyone out there that can help me in how to test the sensors or could point me in the right direction..im realy stuck and santa is on his way and funds are a bit limited...