Dinked around with it today for several hours,,, Cleaned all of the cable ends there are,, changed the battery since it was pretty old & weak,,, was checking the 2 small wires that go to the alt,,, and tested them from the alt end to the pcm,,, ohmed great,,, but was not getting a voltage signal from the grey wire at start up,, which is suppose to happen for the first 10-15 seconds,, just long enough to excite the alt and make it start charging.

Still missing on #3 & #4,, and since all indications was leading back to it being a bad ICM,, I ordered one from Advanced Auto,, the new one I tried the other day was for O'Riley Auto,,and it didn't fix the problem,, so I held my breath & FINALLY,, she started running properly. The scanner said that #3 was still misfiring a bit,,, so I swapped the wire with a different one we had lying around & the miss went away. Noticed a few other cylinders had occasional misses also going on, so we got a new set of wires and all is now good,, no more misses,, AND as soon as I had changed the ICM,,, it must have told the PCM that all was good in the world, because the alt was alt'n 14.5 volts steadily,, even on the inside gauge.

I had called our local electrical shop,, and was told that would most likely happen,,, the alt will sometimes not fire up if the pcm notices a problem with missfiring,, and he was right.

Finally,, at least for a while I can relax on this car,,, at least until the next issue arrives. Thanks for all of you who gave me suggestions!

Thanks, Doug



65 Mustang Restoration

My other project.

Thanks for updating us, hopefully it keeps running good for you!