2001 Ford Explorer Had Remote Starter Put On Since Truck Would Start Set 30

had a remote starter put on since then truck would not start set for 30 minutes truck start. three weeks later truck would not start had to get a jump to start had battery check told by firestone it was good and alternator. 2 weeks later stop again got a jump to start had remote starter check put new battery in ,2 month later truck engine runs but could not go pass 20 speed try to go pass 20 and truck would stall take foot off accel and truck would stay on set for hour truck off start truck and it ran all right please help