2003 Ford F-150 P1131 and P1151

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.