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lostrider, Ford Technician
Category: Ford
Satisfied Customers: 3075
Experience:  ASE Master Technician, Ford Senior Master Technician,Diesel certified, ASE Master, 22 yrs FORD exp.
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1998 Crown Victoria: error codes P0171 and P0174

Customer Question

Hello, 1998 Crown Victoria with error codes P0171 and P0174. Is this just one part or could it be multiple parts. Is there way to deduct what one part I should replace.
Submitted: 8 years ago.
Category: Ford
Expert:  lostrider replied 8 years ago.

Hi and thank you for your question, there are a few things that could cause those codes, the p0171,p0174 indicates a lean condition, most common concerns are vacuum leaks, need to inspect the vacuum hoses on the engine epically the PCV hose to make sure there are no leaks, most of the time it will sound like something sucking air, second, the fuel system can also cause the code, check the fuel filter to make sure it is not restricted or partial clogged, third, the Mass Air Flow Sensor at the air filter box where the big hose hooks to can cause a lean condition if the sensor is contaminated.

lostrider and 3 other Ford Specialists are ready to help you
Customer: replied 8 years ago.
Okay, but when the car is going up a hill, it lags but not when I put the car in 2nd gear, if I don't do this, it lags between 2nd and Drive, say when the transmission kicks into Drive around 50 miles an hour, This is the problem that is setting off the engine light
Expert:  lostrider replied 8 years ago.
as far as the lag, is it more of a shudder feeling?
Customer: replied 8 years ago.
No, it sounds like the engine is choking or misfiring
Expert:  lostrider replied 8 years ago.
I would start looking at the fuel system, has the filter been replaced latley?
Customer: replied 8 years ago.
Yes, the fuel filter has been replaced, I think it is the fuel pump or maybe a short on the fuel pump, I just wanted a second opinion.
Customer: replied 8 years ago.
Any answer would be appreciated.
Expert:  lostrider replied 8 years ago.
do you have access to a fuel pressure gage?
Customer: replied 8 years ago.
No , what would the fuel pressure tell me? I have access to a garage
Expert:  lostrider replied 8 years ago.
the fuel pressure will tell you what the fuel pump is doing, there is a schrader valve on the fuel rail, look like a tire valve stem, the fuel pressure gage will screw onto the valve, route the gage hose to the windshield, where you can see it while driving, tape it down, the fuel pressure should maintain between 30-40 psi, anything below 30 the fuel pump of filter is the problem.
Customer: replied 8 years ago.
Thanks, Have a good weekend
Expert:  lostrider replied 8 years ago.
you too, and thank you.