Hi all this fault is realy taxing me . After a rebuild the ecu threw up p0171 fault . I have checked both maf and oxygen sensors checked for vacum leaks checked fuel pressure and injectors and just about everything that throws up this fault . When running on idle the short term fuel trim is maxed out at 25% while the oxygen sensor is reading 0.1-0.2 volts signallng a high oxygen content hense the high fuel trim but as i said i cannot find any vacum leak and the engine is fuelling correctly. Any input would be very much appreciated.

M.