i am in need of some advise i have a focus mk1 that has error p0172 system to rich i have had lambda sensor changes, fuel filter, ht leads, sparks plugs, air filter changed and still have the error. the car is not misfiring and can not seem to find out what the issuse is can anyone help

Have you reset the code since doing the work?
It could just be that the code is still stored in the system.
Try disconnecting the battery for 20 minutes and see how you go.
Make sure you have your correct radio code first though.