To borrow a phrase from the late Richard M. Nixon, "Let me say this about that."
Many years ago, before there was a
and pretty much before Al Gore invented the Internet, I was having both high idle and "early morning drive-off stall" problems with my '88. The dealership where I bought it had been sold to a bunch of crooks, so I was having service done at a different, supposedly respectable dealership and I mentioned these symptoms to the service manager. He immediately pulled out a reference to the C101 and told me if I had them do a TSB to eliminate the C101 connector it would solve all those problems, make it run cleaner, and improve the gas mileage.
Trusting soul that I am I had the work done -- to the tune of over $500. Two weeks later I failed an annual emissions check ... I had never failed one previously. The early-morning drive-off stall was exactly the same as before. Sporadic high idle was not eliminated. Gas mileage was the same.
When I went back and spoke to the service manager about how this expensive "fix" hadn't corrected any of the problems he said it would fix, his response was "I never said that." Needless to say I no longer use that dealership.
I also have a used 1988 MJ which still has the C101. I have not yet had any of those problems with it. I do not believe the C101 is your problem. It's either the IAC (Idle Air Controller) or the TPS (Throttle Position Sensor).