I have a 99 Disco 2 with 107K on it....on the highway, I get the P0174 code and CE light on - it says left bank too lean - is that my O2 sensors? or something else?

 

What octane gas are you burning, when was it last tuned along with new plug wires and have you replaced your 4 02 sensors yet?

 

93 octane new plugs and wires 16 months ago - I've owned it since the begining, and I can't remember changing the O2 sensors.....my thought was to replace the 4 o2 sensors.......

 

Mike - Shoudl I just replace all the O2 sensors?

 

At your mileage, yes, replace all 4...but if the budget is tight, replace the front 2 O2 sensors first, then the rear. The rear sensors simply make sure the converter is operating properly.

 

How do I know if the converter is working correctly?

 

A good indicator of the converter NOT working correctly is if you smell rotten eggs or sulphur.

 

Ok - I changed the O2 sensors all 4 - was good for one day - now I get P0171, P0174 (lean left and right bank), P0734 - Gear 4 Ratio incorrect......So do I need to replace the MAF - or just try to clean it with electrical circuit cleaning - HELP!

 

Check vacuum lines from the top of the engine back to the intake manifold and ONLY, I repeat ONLY buy a genuine rover MAF.

 

I ordered one from Britsh Atlantic.......I'm assuming that is good correct....