1985 Mercedes Sl Stumble and Hesitate

[samonline]

I drive the car for two to three minutes , the car start stumble and hesitate , if I press on the accelerator , the car died and stop , I have to wait five minutes to drive it back again for two or three minutes to start again hesitating and stumble.
I did ground the wire going to the "oil temp sensor "unit to bypass the the o2 sensor and keep the flow of gasoline higher , no result still doing the same. The gas pour very well to the fuel pump . ( Thanks to Chuck for all these tests) . Any more ideas ??