Why is my 1997 expedition showing a misfire on number 2 cylinder OBD code PO302. Also I am getting code readings PO174 andPO171 system to lean on Bank 1and 2

P0300 Random/Multiple Cylinder Misfire Detected P0301 Cylinder 1 Misfire Detected P0302 Cylinder 2 Misfire Detected P0303 Cylinder 3 Misfire Detected P0304 Cylinder 4 Misfire Detected P0305 Cylinder 5 Misfire Detected P0306 Cylinder 6 Misfire Detected P0307 Cylinder 7 Misfire Detected P0308 Cylinder 8 Misfire Detected P0309 Cylinder 9 Misfire Detected P0310 Cylinder 10 Misfire Detected P0311 Cylinder 11 Misfire Detected P0312 Cylinder 12 Misfire Detected P0313 Misfire Detected with Low Fuel P0314 Single Cylinder Misfire (Cylinder not Specified) P0315 Crankshaft Position System Variation Not Learned P0316 Misfire Detected On Startup (First 1000 Revolutions)

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P2195 O2 Sensor Signal Stuck Lean Bank1 Sensor 1 P2196 O2 Sensor Signal Stuck Rich Bank1 Sensor 1 P2197 O2 Sensor Signal Stuck Lean Bank2 Sensor 1 P2198 O2 Sensor Signal Stuck Rich Bank2 Sensor 1

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P0300 multiple misfire
P0302 misfire cylinder 2
P0306 misfire cylinder 6

PO171 OBD2 Code basically this means that an oxygen sensor in bank 1 has detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1. The P0171 is one of the more common trouble codes.

his code is triggered by the first downstream (front) O2 sensor. The sensor provides a reading of the air:fuel ratio leaving the engine's cylinders, and the vehicles powertrain/engine control module (PCM/ECM) uses that reading and adjusts to keep the engine running at that optimum ratio of 14.7:1. If something is not right and the PCM cannot maintain the 14.7:1 ratio, but rather there is too much air, it triggers this code.

if your saying its a P0302, it means this Cylinder 2 Misfire Detected check here for solutions http://www.obd-codes.com/p0302

P0302 is a misfire in cylinder #2. When was the last time you changed spark plugs? That's the most common cause of a misfire.

Look for vacuum leaks,that are causing the O2 Sensors to go lean, and set codes on both banks

P0174/0171 are bank 1-2 running lean (insufficient fuel) which is related to the misfire codes. When there is a misfire detected, the computer shuts fuel to those cylinders triggering "too lean" codes. These vehicles are known for ignition coil failures. I'd recommend you replace all ignition coils (qty of 8) as they do have a short life span. Replace with another brand (not motorcraft/Ford), such as MSD/Accell/BOSH etc. hopefully this helpd!!

P0171------ system too lean bank#1
Po174------ system too lean bank#2
For these 2 codes, try cleaning the maf sensor (mass air flow), that is mounted in the big black hose that goes from the air filter housing to the throttle plate, if it is dirty, that will cause those 02 sensors to send a signal to the computor to lean the air fuel mixture. If cleaning it doesn't work, the sensors will probably need changing.
P0300---- Random/multiple cylinder misfire
P0316---- Cylinder misfire at start up---- first 100 revolutions.
On those 2 codes, you have to do some testing to find out why there is a misfire.
Possible causes:
dirty/malfunctioning injectors
weak coil pack
fowling spark plugs/wires
Low fuel pressure

complete tune up plugs wires distributoe cap and rotor

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