92 High Idle and Very Rich

So my XJ just randomly started doing this again. Randomly it will start to idle high (1500-2000) and smell very rich. When it does this it will, more often than not, stall out when trying to pull away from a stop. It seems like it's completely flooding the motor out. To get it fired up again I have to 'flood' start it. Once it fires it runs extremely rough and pours black smoke then it will clear up and run smooth. Last time I had a high idle problem the TPS was the culprit, so I swapped it and the IAC without seeming to fix the problem.
The MAP is relatively new and nothing else seems obviously wrong.

Any ideas?

Test the O2 sensors, and inspect the exhaust manifold for cracks.

OK, it turned out to be a fuel pressure regulator. When I pulled the reg there was debris in the passageways. I'm guessing the computer was increasing the idle to deal with the over rich condition at idle.