Yesterday after a drive on the Interstate, about 20 minutes at 70 mph, I stopped in town at a light and my '91 745 Turbo began to idle really roughly, up and down, from about 300 to about 900 rpms, then it would stall out. I could always start it right up again, but then it would surge up and falter and if I didn't keep my foot on the accelerator, it would stall again. I disonnected the MAF sensor and it held an idle of about 800, and then I went home (limped home?), with the check engine light on. I reconnected the MAF sensor, same thing, and so I replaced it with a backup, one I got from someone on ebay, and now the car runs just fine. There were not codes in the OBD memory, just 1-1-1, and the car seems to be better. Go figure.

The throttle body is squeaky clean, the TPS is perfectly adjusted, the throttle pulley is perfectly adjusted, the IAC valve is a 6-month-old Volvo OEM (got it new), and the TPS, the ECT, etc., are new. (I looked at the FAQ re. "idle surge and hunt" and it didn't apply to this situation.)

Are the symptoms I described (which I experienced before, about a year ago, and then they went away) signs of a bad MAF sensor or could this be one of those intermittent gremlins that drives one utterly and completely MAD, and causes one to give up and buy one of those transportation appliances my wife likes made by Japanese company beginning with T?

Thanks for the help.
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Darius in Albany NY '86 744 GLE (175K, given to my mother-in-law); '91 745 Turbo (167K-my 'Little Red Wagon')