Mechanics

PO171 AND PO1131

1998 Ford Contour • 4 cylinder 2WD Automatic •

1998 Ford Contour ford contour PO171 and PO1131
OH the horror. I have a 1998 ford contour se 4cyl. I am pulling a P1131 and PO171 code. I have fuel pressure between 30 and 45. I have replaced the front O2 sensor the air filter the fuel filter, the spark plugs, cleaned the MAF, replaced intake gaskets and one faulty vacumme hose. Reset the computer and THAT DARN LIGHT came back on! Oh and did teh carb clean test for varience in motor when sprayed over and around vacumme hoses and get no varience. The fuel trim both long and short are at zero. Whats left? Where do I look next to find the problem?

Please note the codes P1131 and PO171 have come back after all of this work and resetting the computer. So again I ask What could it be?
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Kakes68
July 22, 2011.




They are both lean codes and usually the result of vacuum leaks somewhere. It can also be an air leak in the intake snorkel between the MAF and the throttle body or a problem with the MAF.

Wrenchtech
Jul 22, 2011.
Thank you wrenchtech. The MAF is good. I did a simple tst as I ive close to sea level and the barometric was close to 26.5. MAF is good. Snorkel appears in good condition no holes that I can see. How do I do a smoke test as the carb test shows no variation in motor as it did before I fixed vacumme hose and intake gasket. COuld it be the # o2 (after the catalitic) sensor is bad?

Tiny
Kakes68
Jul 22, 2011.
No, it couldn't. Your MAF test didn't prove anything except that the baro is reading the barometric pressure. That has nothing to do with the air flow measurement.
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Wrenchtech
Jul 22, 2011.

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