I have an 01 f150 with mutliple codes. the truck was running bad a few months back and when i checked it out the pcv valve had somehow popped out. i put it back in and kept driving. spark plugs needed changing and i ripped a wire.bought new set and only changed half of the wires for labors sake. could half old, half new wires cause it? (I doubt but just checking) I have since checked the pcv valve again and it's still in but it doesn't seem seated all the way or as snug as it should be. could that be the problem? any ideas would be much appreciated. P0401 powertrain-exhaust gas recirculation flow insufficient
P0171-powertrain-system too lean (bank 1)
P0302-powertrain cylinder 2 misfire
P0305-cylinder 5 misfire
Emission leak (small leak)
P0401 powertrain-exhaust gas recirculation flow insufficient This is more than likly your EGR Value they tend to stick. you can try cleaning it. some times that works. but that is just short time fix.
P0171-powertrain-system too lean (bank 1) one of 5 things 1. Fuel System:A malfunctioning fuel system can reduce the amount of fuel coming into the engine, causing a run lean condition. A clogged fuel filter can reduce both fuel delivery and fuel pressure. Low fuel pressure will reduce the fuel flow at the fuel injectors. 2. Oxygen Sensor:O2 Sensors are used to monitor the amount of oxygen in the engine's exhaust. The on-board computer uses the information from the O2 sensor to make the air/ fuel mixutre richer or leaner. If the oxygen sensor malfunctions, it can send the computer incorrect information about the current state of the exhaust.
3. Air Mass Flow Sensor: The air mass flow sensor monitors and tells the on-board computer how much air is entering the engine. As the air flow into the engine increases, the sensor sends a signal to the on-board computer to increase the amount of fuel being delivered to the engine. If the sensor does not send an accurate signal, the air flow could increase without a corresponding increase in fuel.
4. Air Leaks:Engines have a sea of hoses of various shapes & sizes. These hoses do not last forever. Constant exposure to high heat will eventually cause a hose to deteriorate. If this hose is not replaced, it will cause an air leak. When an air leak occurs, excess air finds its way into the engine.
5. Computer Malfunction:On-board computers monitor every aspect of the engine's operation - but that doesn't mean that the computer cannot develop problems. Any electronic device can malfunction. The computer could fail to send appropriate fuel delivery signals to the fuel injectors, which would cause the engine to run lean.