95 mystique 2.5L p0171b/p0174b codes

[ed95mystique]

these codes just came up and i think they are Bank 2 System Too Lean / Bank 1 System Too Lean or i might be wrong i really need some help on this i put so many new parts on this car but it seems as soon as i fix one problem another comes out so can anybody tell me how to fix this problem.

[G O R T]

If these codes came on suddenly and you have not replaced the intake gaskets before, you probably have a vacuum leak there.

http://www.contour.org/mods/mods.php?s=howto&displayid=17

[ABE]

Yes, those codes are for a too lean condition on bank #1 and #2.

This can be caused by:

1. weak fuel pump pressure;
2. fuel filter partially plugged;
3. fuel regulator faulty and reducing available fuel pressure;
4. PCV hose damaged/leaking;
5. other vacuum leak;
6. Sticking Idle Air Control (IAC) valve;
7. intake manifold gaskets leaking.

From all the symptoms it sounds like a weak fuel pump that is overheating. This could be aggravated by a blocked filter. If you don't know when the filter was changed (should be annual) then change it now. The fuel rail has a schrader valve where the fuel pressure can be checked with a gauge. It would be very dangerous to just press the center pin to see if there is any pressure since it is supposed to be about 40 psi..

The fuel regulator has a vacuum connection that reduces fuel pressure under high vacuum (idle). Remove the vacuum line and plug it, to see if the performance improves.

If the fuel pressure is good and consistent then look for vacuum leaks. The PCV is a prime target here. Replace the PCV valve if you cannot hear the balls inside when shaken. Check the PCV hose carefully for any damage and cracks by bending it. This is very special hose so do not substitute. Bend all vacuum hoses to see if rubber is cracked, replace if it is. Check for loose connections to fittings.

The idle speed is controlled by the IAC and it can be sticky. Try removing the electrical connection to see if engine stalls. If it does then not likely a vacuum leak or gasket leak. The IAC is the round bodied device attached to the throttle body. Remove it and clean the body with throttle body cleaner. Ford recommends replacement and not cleaning, but your symptoms don't match a typically faulty IAC where engine speed goes up and down significantly.

Hope this helps.