What is the reason why the old Audi v6 can't start when the throttle plug is unplugged?

The old Audi v6 can be started by unplugging the throttle plug for the following reasons.

1, the mixture is too thick or too thin.

2. The ignition timing is inaccurate.

3. The cylinder pressure is not up to standard.

4. The sensor is damaged, resulting in inaccurate data from the engine to the ECU.

5. Air leakage in the air intake system and carbon deposition in the throttle valve, fuel injector and air intake pipe.