During the last few test drives, I experienced the issues during a full throttle acceleration from a dead stop; which never happened before. Also, the LS went into ETC safety mode with an idle only condition twice. When this happened it set a P2112 (throttle actuator control system - 
stuck closed) and a P2104 (throttle actuator control system - forced idle). Now how do these three codes and symptoms all relate with each other?
I already checked for the common bad coil issue. I check the COP ignition systems for bad coils by back probing the main coil power feed with my scope on glitch capture and using an injector as my cylinder reference. I will do what I can to try to find a bad coil. This includes idle, cold, hot, snap throttle and/or power brake. I look for a positive or negative voltage spike on the coil ignition feed which will indicate the failing coil(s). This car passed this test with absolutely no problems. I also never felt a 
single misfire while driving this vehicle. After much contemplating, I came up with a theory. I know these Lincoln LS’ often stall because of a voltage spike from a bad coil to the PCM. I got out my extra long test leads and went for a test drive. During the event I caught an ignition voltage spike. I compiled some more data on this problem and could see that right after the spike I would always lose the injectors and sometimes even lose ignition primary. I also wanted to check my electronic throttle control issue. With my scope hooked up to ignition primary (glitch capture), and both throttle position signals (one on glitch capture), I captured the voltage spike on the TPS signal. The voltage spike is what cause the ETC codes and my other two problems.
What I think was happening is the coil would only fail under very high load and when it would fail, the voltage spike was always big enough to knock the PCM down. If the spike was smaller there would have been misfire complaints and P0300 codes instead of all the issues this one had. All of these issues make sense now, but sometimes you get pulled in and down the wrong road and you need to know when to turn back.
