Where is my PIP sensor located on my 1990 Ford Thunderbird SC 5 speed?

I have replaced the DIS module, fuel regulator, coilpack, ECM, EGR valve, PCV valve, plugs, wires, air filter, oil filter, and checked every vacuum line and electrical connection I could exept that. I dont know where it is. The car runs while cool, but when it gets up to operating temp, it begins bucking and the tach sweeps wildly. I dont have time to take it to a dealership so, if I could just find where that part is, I'll replace it and get this thing out of my hair. Sexy car though.