Have 1989 Jeep cherokee 4.0L with auto Tranny. The transmission shifts out much too low, I have tried to adjust the TV cable at thottle body but seemed to have no effect. the tranny will shift 15 and 25 mph even under full thottle if not manually shifted what else could be going on here. does tranny get input from tps and what should I look for as in voltages from sensor if it does