I've been trying to get the drivability back to normal in the 87' GT I bought. It would start fine and idle at a normal 800ish rpm, then after driving for a little bit, the idle would climb to 1400 or so. I read through the high idle check lists. Long story short, I replaced all the sensors, (O2, IAC, ECT, ACT, EGR delete)all motorcraft where applicable, replaced the dry rotted vacuum lines, double checked timing(13 degrees). Still had the idle issue. I had originally set the TPS to .95. Checked it again the other day and the voltage was 1.8. Figured the sensor was bad so put a new motorcraft TPS sensor and the voltage was still about 1.8. After drilling out the holes, the best I could get it down to was 1.1. The reference voltage was 8.1 volts. What would be the most likely cause of this high voltage? I traced the reference wire back, and where it meets the EGR wire, some of the sheathing has came off but the wire still looked good. I wouldn't be upset if I had to replace the computer, bc a MAF conversion with an A9P was going to be the next thing I do to the car.