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This is what the service manual states:
The Powertrain Control Module (PCM) monitors the heated oxygen sensor (HO2S) activity for 90 seconds after ”Closed Loop” has been established. During the monitoring period the PCM counts the number of times that the HO2S responds from rich–to–lean and from lean–to–rich and adds the amount of time it took to complete all transitions. With this information, an average time for all transitions can be determined. The PCM then divides the rich–to–lean average by the lean–to–rich average to obtain a ratio. If the HO2S transition time ratio is not within this range, Diagnostic Trouble Code P1134 will be set, indicating that the oxygen sensor is not responding as expected to changes in exhaust oxygen content. DTC P1134 is a type B code.

You could have a lazy or dead bank one upstream O2 sensor (B1S1) or the RH bank air fuel ratio is way out of spec and cannot respond the B1S1 O2 sensor input.
 

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Soo the oxygen sensor one of those is going bad?
There are four heated oxygen sensors (HO2) and two catalytic converters on your truck. There is a HO2 sensor located between each catalytic converter and the engine. There is a HO2 sensor located after each catalytic converter.

The failure code is being set because the output signal for the HO2 sensor located before the RH bank catalytic converter is not producing the correct signals. The first thing to do is replace that sensor and see if it fixes the problem.
 
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