P0171 Ford - 2005 4.2l

Question

Is there more specific help on a 2005 ford freestar, 4.2l with code P0171

Answer 1

P0171 Fuel trim lean Bank 1

Vacuum lines, how the vacuum line for a Ford this is a promissing problem. On the worste side it P0171 would be a mechanical condtion. such as coolant entering a cylinder combustion chamber and seting a lean code for that particular bank.

 Vacuum hose that breaks set a variaety of DTC with a lean bank code. This vacuum line set a lean code and a rich code and a EGR no flow. Its very important for that the  vacuum lines be checked

 

On this Ford, there is a Lean Bank code for Bank 2. it also smelled of coolant from the exhaust, at start up..At idle it ran smooth with no misfire code condition , the only code was a Lean Bank code. feeling the upper radiator hose it was noted to be over pressurized. and in the radiator tank you can see bubble rising, to confirm the cylinder head had a problem a leak down test was performed , opening the radiator cap and doing the leakdown revealed a cylinder head was at fault.