99 ranger check engine problem! please help

1999 FORD RANGER
144,000 MILES • 3.0L • V6 • 2WD • AUTOMATIC
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ZALATOY
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  • 4 POSTS
Hello I have a 1999 Ford Ranger 6v 3.0L Flex Fuel and my check engine light is on codes p0171 and p0174 (lean bank #2) I changed maf sensor, checked vacuum leaks, put new air filter, new fuel filter, new hoses, added a SeaFoam and I still have the problem! i checked fuel pressure and its 35 psi. some people say to change fuel injector damper and some say fuel pump! (fuel pressure regulator comes with fuel assembly)... don't know what to do need help from a pro


Nov 4, 2014 at 3:10 AM
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JACOBANDNICKOLAS
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Actually, the fuel pressure is weak. With the engine running, it should be 47 to 63psi. With the engine off, it should be 55 to 65psi. Since you have a lean mixture, I suspect the low pressure is the cause.
Nov 4, 2014 at 9:43 AM
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ZALATOY
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  • 4 POSTS
can that be caused by the fuel injection damper? or is it the fuel pump going out?
Nov 5, 2014 at 12:38 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,246 POSTS
The damper is there just to absorb pressure waves in the fuel rail caused by injectors. It doesn't control the pressure like the regulator. If the fuel filter is good and there is nothing blocking fuel delivery, my guess is the pump.
Nov 5, 2014 at 12:45 AM
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