I have a f150 with a pending code p0171 what can
Could be a few other things, but starting with the most common :
Intake air leaks, have you changed the air filter as of late, or installed an aftermarket air intake ( K&n, etc ) ?
- If so, check the entire intake to make sure the assembly is correct, this would be in the area after the MAFS ( Mass Air Flow Sensor ) which is in part of the factory air filter housing ( it is that post with the wire in it ).
Other Air leaks after the MAFS
- The most common place for air after the MAFS is the Rubber elbow on the back of the throttle body. The rubber 90* boot will get hard and crack, causing air leaks. This is a 25.00 ( ?) item at a Ford dealer, and easy to change. Check this from the 90* to the other end. This is usually the cause of a P0171 code, but not the only.
EGR leaks. Some times the diaphragm in EGR will be the cause of the problem. This is the flying saucer shaped dish on the driver's side of the engine.
Exhaust leaks by the O2 sensors. If you recently had exhaust work done, this could be the cause of it. With the factory SS system still intake, this is usually a non issue.
When you complete a repair ( if the Car MD will not clear the code ), you need to have 2 drive cycles to get a pending DTC cleared.
For Ford, this is 2 drives, starting with the engine warmed up, normal throttle drive up to a speed of at least 47 mph, and maintain with steady throttle for 10 min. Back down to a stop, and then repeat this for the second time. Fuel tank needs to be at least 3/4 full ( think that is it ) when doing this.
There are a few other items that have to do with the vapor recover, excessive fuel pressure, leaking fuel injectors or fuel regulator, or a low fuel pressure condition. These are not as common for the error.
Starting with the rubber vac line on the back of the intake, looking for cracks is a good place to start.
Nov 14, 2009 |
2005 Ford F-150