Hello I have 99 Linc. Nav. AWD, It has an issue with the electrical system. The theft light flashes faintly and rapidly when under a slight strain like small to moderate inclines. It has completely stalled on me to times.Another case it lost all power but, the engine kept running at a low rpm and you could not rev it up with the accel pedal and the most recent issue was it jumped out of gear while going up a small incline. Every time I have had an issue with it I pulled off to the side of the road and turned the ign switch to off and turned it back on and it will run fine. I have read a lot of threads but, none seem to match mine exactly. Any help would be appreciated. Thanks
Are you using the factory key with the chip in it?
I know that some aftermarket devices (fits inside the column) allow you to operate the vehicle with via a regular key because it overrides the factory anti-theft device. Otherwise it sounds like a problem with the factory key/ignition system and I unfortunately cannot help you.
I have been doing quite a bit of research on here about potential problems and the biggest cause of electrical gremlins is a leaky windshield seal. The GEM/fuse panel will get water in it and cause a short. Just my 2 cents.
The factory anti-theft system CANNOT cause an engine to stop running once it has started. You can rule that out. Wet GEM modules and fuseboxes typically manifest as intermittent or uncommanded accessory operation.
You might have a bad ground in the electrical system, but I'd replace the PCM Power relay first.