1991 244, starts just fine, drive a few miles, shut it off, then try to restart and you can crank and crank, with an occasional back-fire (sounds terrible when that happens, I just see stuff inside the engine breaking). And, sometimes, if you crank lonnng enough, it'll start up, but if you take your foot off the accelerator and let it idle, she dies. Then you get to do the "cranking, back-firing then maybe it'll start" exercise. I've found that if you give it a little throttle and let it run for a while before removing your foot and allow it to return to idle, then it'll idle without dying.
Bear in mind, it is 104f outside.
It did this just a couple hours ago when my wife and I went to get some groceries. I had a used MASS in the trunk, so I swapped it out, and it started right up as if nothing was wrong, so I says "ah-hah, bad MASS, now good MASS, everthing is wonderful" and we drive home, only for it to do the "no start" number again about an hour later WITH THE REPLACEMENT MASS IN PLACE! So, I swap out the ECU, no go, so I clean the Idle Control Valve and check it's operation, no go, so I go into the house, go back out in an hour and she starts right up, better than she has since she came outta the showroom.

Now guys, I am ashamed to tell you this but, I am a mechanical engineer, Masters Degree and all, member of ASME.........................alright, alright quit the laughing, sheeeeesh, I used to design and build prototype heart valves and stuff before a couple old Nam wounds caught up with me!

HELP! I gotta get Old Blue running so Momma can get to work on Monday.