thank you for the question hope this helps.
Well Anytime you get a p0171/p0174 code you are getting air into the intake that the computer does not "know" about. This is due to bad readings from the MAF or air entering the system after the MAF. this is not a bad 02 code.Vacuum leak. Look for defective PCV valve grommet or hose, check all vacuum lines. If all OK, the next step is to check the intake manifold gasket for vacuum leaks you can do this with a smoke machine, or a good can or carb cleaner. the engine will bog down if you find a leak with carburetor cleaner.to check the MAF remove the air intake tube were it goes into the engine and look to see if it has any build up on it. any build up of carbine will cause it to malfunction. remove and clean with carb cleaner. this a Colman problem with fords. in Meany cases you will need to replace the MAF sensor.were is what you are looking for