99 Ranger check engine problem! Please help

ZALATOY

MEMBER
1999 FORD RANGER
3.0L
V6
2WD
AUTOMATIC
144,000 MILES

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

3 Replies

JACOBANDNICKOLAS

MECHANIC
108,139 POSTS

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.

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Tuesday, November 4th, 2014 AT 5:43 PM

ZALATOY

MEMBER
4 POSTS

Can that be caused by the fuel injection damper? Or is it the fuel pump going out?

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Wednesday, November 5th, 2014 AT 8:38 AM

JACOBANDNICKOLAS

MECHANIC
108,139 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.

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Wednesday, November 5th, 2014 AT 8:45 AM