How do I fix these codes?

I have three active OBD II codes for my "99" Disco II. They are P0171, P0174, and P0734. The last one says Gear 4 Ratio. What does this mean? What needs done? Help...

I have found out that the P0734 code may have no real value to me. I still am not sure about the others... :banghead:

those codes are for a mass air flow sensor hope it helps

I would pull power from the ECU to reset and try swapping with a known good MASS AIR. Drive the truck around the block, make sure to get through your gears under a load [heavy on the skinny.] The engine is running rich so I would also have a look at your o2 sensors. Check your code read out and see what you have.

Here is a full list of codes: http://www.disco2.com/tech/v8ems/faultcodes.phtml

Also, checkout www.get-rhino.com (http://www.get-rhino.com/) we need the exposure. :)

RedRhino, That's a great site of all the codes, now I don't have to look them up in the manual!! I agree about the O2 sensors, since it's a 99, the O2 sensors could be bad, especially if the car has been running rich for a while. The O2 sensors start to fade very quickly when the engine is running rich.

Just doin my portion...

Check out www.get-rhino.com (http://www.get-rhino.com).

Hi ...Ive had many codes in the past.. even ones that tell me o2 sensors + mass air flow.....It ended up being a stuck thermostat after all the $$$ and headache....