Cadillac Repair: 96 Cadi Fleetwood Brougham, coolant temp, engine coolant

Question
  My car has recently been acting up. Whether stone cold or running temp, idling or while driving, it will race up then slow down, occasionally refuse to accelerate (stumbles), and stalls. Its hard to start. Sometimes it stalls as soon as I put it in gear. The code PO118 (engine coolant temp sensor circuit high voltage) shows up and I have replaced the sensor twice within the past few months.
  One other question: my headlights will flash on and off repeatedly for no reason while driving or when in park. I have had several Caddy experts/enthusiasts look at it but it remains a mystery to them. It's sporadic and eventually corrects itself but it is very annoying and distracting to me as well as other drivers.

Answer
You will need simple electrical schematics, Test procedures and picture locations of the components within the system that is causing you problems of which can't be done on this website which only allows one picture. I do not have a website so you will have to e-mail: onlineautohelp@msn.com in order to obtain the information.