Audi Repair: Engine start and cut off seddenly, air flow meter, mass airflow sensor

Question
QUESTION: My 96 A4 B5 start briefly and trip when the rev counter reach 1 rpm. it all last thursday after warming the engine for five minutes. As i was ready to go to work, engine will stop as i accelerate to move. i tried for servaral times but could not move the car. Anytime the engine rev is increase from idle, it      trips. later  after work, i tried and it started but when rev above 2.6. to 3. it trips to lower rev and regain speed without the engine stop{just up and down}. i drove to workshop for scaning but didn't recorded any alarm. Fuel pump was checked and it was ok, changed fuel filter.I drove back home 3 rpm engine. One mechanic was saying that it timing. after setting it , no sign of improvement.
Currently, it will start briefly and stops at1 rpm. please note prior to every trip, a relay 208 trip simultaneously then the engine goes off. please eeee help me


ANSWER: I would check the Mass Airflow sensor.  How many miles on the car?  Let me know,  Jan

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QUESTION: the air flow meter was ok.After swaping with another air flowmeter no changes were seen during start up. rescanning for two time doen't reveal any alaram. Currently the milage is 110k. please can any of the input sensors like air flow meter,coolant sensor,canshaft,oxygen sensor,speed sensor prevent the engine from idling.

ANSWER: Could there be an exhaust blockage?  is the air filter clean?  What is relay 208 on your car?  Let me know,  Jan

---------- FOLLOW-UP ----------

QUESTION: The exhuast is ok because anytime i start you feel the exhaust gas coming out.For the air filter i recently bought it. we even remove the rubber hose and it didn't idle after starting. the relay 208 according tn the mechanic is the fuel relay and anytime the rev counter tries to move pass 1rpm, this relay trip and the engine stop or the rev counter goes down. It will try to recover but the moment it passes the 1rpm mark this relay trips.

Answer
Perhaps the crank position sensor is on the way out, and when the engine revs up it cannot keep up.  If the crank position sensor does not give the pulses to the ecu, the fuel relay is tripped...  Try another crank position sensor...  Let me know,  Jan