IHAVE A 87 JEEP COMANCHE 4.0 AUTOMATIC TRANS. AT HIGHWAY SPEED IT HAS A MISFIRE AT ABOUT 50 MPH. IT ACTS LIKE A TIPICAL TPS PROBLEM BUT I PUT IT ON THE LAB SCOPE & VOLTAGE AND WAVEFORM ARE PERFECT. I HAVE EVEN REPLACED IT WITH KNOWN GOOD ONE AND PROBLEM STILL... Login to read more.