This paper addresses the problem of processing eventtiming queries over event streams where the uncertainty in the values of the timestamps is characterizable by histograms. We describe a stream-partitioning technique for checking the satisfaction of a probabilistic timing constraint upon event arrivals in a systematic way in order to delimit the "probing range" in event streams. This technique can be formalized as a probabilistic timing join (PTJoin) operator where the join condition is specified by a time window and a confidence threshold in our model. We present efficient PTJoin algorithms that tightly delimit the probing range and efficiently invalidate events in event streams.