2003 Ford F150 P1131 and P1151

2003 FORD F-150
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STEELEJH
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Engine Mechanical problem
2003 Ford F150 V8 Four Wheel Drive Automatic

I'm having some issues, with the O2 sensors on my truck. The original code that came up was P0171, so I changed the offending O2 sensor. No luck code came back on, found exhaust leak on Bank 1 side, tightened bolts. New codes came up 1131 and 1151, no detectable vacuum leaks anywhere, MAF wire is spotless,checked output voltages of the MAF, IAT and all the O2 sensors, all seemed to be working when they should and outputting the normal voltages. Only thing that I have observed is the the response time for the O2's switching back and forth from rich to lean seems slower then it should, not sure if this is the problem or a symptom.
Apr 29, 2009 at 5:48 PM
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BMRFIXIT
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CARRY OUT A VISUAL INSPECTION ON THE INTAKE AIR SYSTEM AND ALL VACUUM HOSES
Check the intake air system for leaks, obstructions, and damage.
Inspect the entire length of all the vacuum hoses for:
proper connections.
damage or cracks.
damaged or cracked vacuum tees.
Verify the integrity of the positive crankcase ventilation (PCV) system.
Verify the proper PCV valve part number
Apr 30, 2009 at 5:35 AM