As the basic TCP congestion control algorithm cannot distinguish between congestion event and bit error event, it fails to perform well in wireless networks. In this paper, we propose modifications to the basic TCP congestion control algorithm so that its performance is enhanced in wireless networks. In particular, our algorithm refines the multiplicative decrease algorithm of TCP NewReno. We are using some statistical counters to track the frequencies of the occurrences of timeouts and 3-dupacks. Different ratios of these counter values are then used to differentiate a congestion event from a non-congestion event. We are also tracking the time difference between two consecutive timeouts to figure out whether timeouts are caused by network congestion or random bit errors. We tested our proposed algorithm using the Network Simulator version 2 (ns-2) and found that it shows better performance than any other TCP variants in the wireless networks. Moreover, our algorithm is end-to-end in nature and modifies only TCP sender's algorithm.