P0108 Map Sensor; Running Rough, Stuttering

2001 T&C EX 3.8: 108,000 miles, started running very rough at all RPMs, nearly stalling at idle - threw a P0172, system too rich.
- Cleaned intake, checked vacuum hoses, sprayed brake cleaner looking for leaks, it seemed to accelerate slightly while spraying at the connection of the pipe from the EGR to the Manifold; repaired the gasket; resolved.
- Manual/visually check wiring.
- (O2 sensor (forward) replaced at 100,000)
- Disconnected negative battery terminal for an hour to clear PCM history.
- Now it throws a P0108, Map Sensor, and after warming up, it would not want to idle less than 1800, all while still running rough.
- In addition, at times it would run perfectly for 5-10 miles, then suddenly stutter for no apparent reason.
- Also, under full acceleration, it would hit 4500rpm & then roll back and cycle rapidly between 3500 & 4500.

Replaced the MAP sensor (I'm a DIYer, even though I know swapping parts just because for a code doesn't necessarily mean the part is bad)
- Helped the idle rpm problem, and thought everything was resolved, except everytime I clear the P0108 code, it starts running again, throw the code, and on the next re-start it would settle back down again and run prettry good. Why would clearing the code somehow make it take a step backwards?
- Now on the next 10mi jaunt just when I think everything is running well (even though the CEL is still on) it starts stuttering again at about 60mph. It won't stutter if accelerated firmly, but if accelerating slightly or decellerating slightly, it stutters badly.

Can't seem to get anywhere with clearing the code, and stopping the inconsistent rough running and stuttering. Ideas?