I have a 95 Mustang GT 5.O SN95 that has been random surging RPM's for months. It happens about 20 minutes after I start driving on the highway or streets. The car don't move any faster but will jerk if I'm on the highway & the RPM surges. It surges anywhere from 1000 to 2000 above normal. I changed cracked vacuum lines, cleaned the MAS & throttle body 5 times, lubed the springs & cables on the throttle body & cleaned and tested the iac, none fixed it. I tested the TPS, it wouldn't go below 1.09 volts throttle closed and 4.85 wot. I bought a new TPS & it reads 1.38 volts throttle closed. Car has more power & responded better but RPM's surged but not as high or as much. The TPS is non adjustable, any help would be much appreciated.