Ford Mustang v6 2007 P0171 and P0174 codes help!!!

Hi All,
I own a 2007 v6 mustang and last week the service light lit on and the car suddenly suffer a lack of power and hesitation on acceleration(rpm´s going up and down when i push the accelerator), this is not happening all the time, actually when i start using it, it works great, but after some miles it starts with the issues. I used a scanner to read the codes and it gives me the P0171 and the P0174. some one told me it could be caused by the gas pump...


Can anybody help me???

thanks

Yes you can help yourself. It's the most common set of codes on the most common brand on this site. Read the million forum posts about 171, 174 on here first before throwing another on the pile. All the answers you seek are there.

Your car starts up in open loop fuel operation. When the engine warms up to about 180f the engine goes into closed loop fuel control. When in this mode, the ECU uses sensors & various actuators to run the engine. Essentially the ECU can tell if the fuel ratio is in correct proportion to the airflow measured via the MAF sensor. If the air/fuel supply does not match the fuel tables in the onboard computer, within certain limits, or is not able to obtain stoichiometric control at 14.7 to 1 air/fuel ratio,then the computer flags a problem via the check engine light. Your computer has determined that there is a lean fuel condition. The cause can be many things, but basically, if all the sensors are working properly, there is an air leak in the intake or vacuum lines or a fuel restriction. You need to find this leak or restriction, & correct it then clear the engine light.
On this engine there is a good possibility that you have a leak in the intake manifold. You can often find this type of problem with a can of carb/intake cleaner, especially if the idle speed is uneven. You have found the leak when the idle returns to normal.
Change your fuel filter and get fuel pressure checked first then work on the list below.


* MAF sensor (contaminated, damaged, malfunctioning, etc.)

Fuel System

* Fuel pressure regulator (leaking, malfunctioning, etc.).
* Fuel filter plugged, dirty.
* Fuel pump (weak, check valve leaking, etc.).
* Leaking/contaminated fuel injectors.
* Low fuel pressure or running out of fuel.
* EVAP canister purge valve leaking (when canister is "clean").
* Fuel supply line restricted.
* Fuel rail pressure sensor (incorrect reading).

Air Induction System

* Air leaks after the MAF.
* Vacuum Leaks.
* PCV system (leak, valve stuck open, etc.)
* Improperly seated engine oil dipstick.

Exhaust System

* Exhaust leaks before or near the HO2Ss (exhaust manifold gasket, mating gaskets, etc.)..

EGR System

* EGR valve tube/gasket leak
* EVR solenoid vacuum leak

Secondary Air Injection

* Damaged/malfunctioning secondary air injection system (mechanically stuck valve).

Good luck, Aeroman.

so what was the outcome?

what needed to be fixed or are you still having problems?