Help with MPI/MPFI faults (Audi A4 B5)

Malfunction	Its reasons	Your help
A. Cold engine does not start or starts poorly	1. Defective fuse 13, 21, 25, 27 or 28 2. The fuel pump relay is faulty 3. The fuel pump does not supply fuel or supplies an insufficient amount 4. The fuel pressure regulator is faulty 5. The idle speed control valve is faulty 6. The control unit is faulty 7. No signal from the engine speed sensor 8. Additional air enters the engine	Replace Check, replace if necessary Check for gasoline in the fuel tank Check the fuel pump, measure the amount of fuel coming in Measure the pressure in the workshop Check it out Check in the workshop Check the entire length of the wire Check all hoses
IN. Warm engine does not start or starts poorly	1. Defect in the vacuum hose to the fuel pressure regulator 2. See A 1–4, 6 and 7 3. Injection valves are leaky 4. Coolant temperature sensor is faulty	Check the hose — Check the valves Check the sensor
WITH. The engine starts, but soon stalls again	1. See A 1 and 5 2. See B 1 3. The CO value does not correspond to the norm 4. Defective air mass meter (MPI) or intake air temperature sensor air or in the manifold pressure sensor (MPFI) 5. Throttle potentiometer is faulty	— — Check the injection in the workshop Check it out Check it out
D. Cold engine shakes at idle	See A 5	—
E. Warm engine shakes at idle	1. See A 4 and 5 2. See p. 3	—
F. Too high revs when engine is warm idle	See A 5	—
G. The engine runs intermittently	1. The fuel filter is clogged 2. See A 3 and 5 3. See B 3 4. See C 3 and 4	Replace the filter
N. The engine runs intermittently and switches off	Uneven fuel supply from the fuel pump	Measure the amount of fuel supplied
I. Insufficient engine power	1. See A 3,4 and 8 2. See 3 and 5 3. The throttle valve does not move to the full throttle position	Adjust the throttle cable
J. Engine backfiring into intake manifold	1. See A 4 2. See p. 3
TO. Fuel consumption too high	1. See B 4 2. See p. 3