2003 range rover hse gremlins

[steviedcorp]

Hi all I'm new to the forum. I have had these trouble codes on and off for the last 6 month. I replace the Maf, fuel pump,fuel filter, o2 sensors, oil separator, spark plugs, all the pcv hoses and vacuum lines. Please help these codes are killing me
thanks
steve

 

[joey]

Welcome to the forum.

What codes do you have?

 

[steviedcorp]

Hi Joey Thanks for the quick response. I have had Po171, p1172, p1173,p1175 and sometimes p1174. they did a smoke test but didn't find any cracks in catalytic converter. however bank 1 cat is the original one???
Thanks for the help.
steve
03 RRhse

 

[joey]

What kind of Air filter do you use? And is the factory cover on the filter assembly fitting properly and tight?

 

[steviedcorp]

Joey, I use the stock air filter its new and the airbox is sealed tight with all its clips. Today the ideal when from 750 - 500rpm then back to 750 rpm at a light. no check engine on yet since I cleared it but I'm only at 24 miles since reset