Should I be able to tell if there is power to the o2 sensor plug simply by using a circuit tester.Drove through a large puddle over a year ago and truck suddenly started running rough.Have replaced pretty much everything on it even computer and same problem.Starts right up then after about 5 min starts sputtering then eventually cuts off.Just replaced the o2 sensor and decided to test the plug first and doesn't seem to have any power to it.

 

Did you get water in the distributor? Take off the cap and make sure it's dry.