Here is the info from the repair manual, it's quite technical, but what it is saying is that if this is the only code that is stored, you have an issue with the fuel mixture or the O2 sensor system. Was this code originally set and the reason for replacing the sensor? Where did you get the new sensor, and what brand is it?
Trouble Code: P1134 (3.4L V6)
HO2S-11 (Bank 1 Sensor 1) Transition Time Ratio
Trouble Code Conditions:
DTC P0101-P0103, P0107, P0108, P0112-P0118, P0121-P0123, P0125, P0128, P0201-P0206, P0410, P0440-P0449 and P1441 not set, engine speed from 1000-3000 rpm for 3 minutes in closed loop, system voltage over 10.0v, ECT sensor over 167ºF, MAF sensor from 10-30 g/sec, gear selector not in Park or Neutral, and the PCM detected the transition time ratio was less than 0.4 or more than 4.5 during a 100 second monitoring period.
Possible Causes:
* Air leaks present in the exhaust manifold or the exhaust pipes
* Fuel pressure is too high (i.e., causing a rich air fuel mixture)
* HO2S may be contaminated (due to improper fuel or silicone)
* HO2S signal high or low reference circuit has high resistance
* HO2S heater element has failed, or the heater circuit is open
* PCM has failed
