On my 97 SL320 and 97 C280 ( M104 with ME2.1 injection ) if I create a miss fire by shorting a plug or disconnecting the injector wire, the computer sees the miss fire then shuts off the injector to prevent raw fuel from damaging the cat converter. Cycling the key will bring it back online. In your case, something is causing the computer to see a miss fire.

Do a compression test and a leakdown test to make sure # 2 is building enough pressure.

Also look at scan tool miss fire counts for all cylinders.