Error 17656: How to Fix It & Troubleshooting

Hello.

I drive a Skoda Octavia with an AHF engine. Around Christmas time, I noticed that the car 'doesn't have much power anymore.' It might be okay in the flat countryside, but here on the Upper Rhine, there are quite a few more hills. I've already replaced the diesel filter.
LMM (Mass Air Flow sensor) was replaced today, but unfortunately, there were no positive results. I have performed several measurements using the adapter. The result after replacing the LMM is:
Measurement block 3, field number 3: 450-460 mg/h (too high), should be 230-370.
Measurement block 3, field number 4 is 4.8%. The target range is 40 to 75.
Everything is idling. At full throttle, the values are:
Measurement block 3, field number 3 is 415.
Measurement block 3, field number 4 remains at 4.8%.
The car now has 82000 km on it. I took it to a Bosch service center, and they told me the fuel injection pump is defective . The repair, including a timing belt replacement, costs €1500 . I hope someone can help me so that the repair isn't so expensive. If anyone wants to see the measurement protocols, I will send them immediately... Oh yes, the test for the needle lift adjuster (knock test) was negative!!!!

Best regards, Klausi.

Hello,

What coolant and intake manifold temperatures did you measure at idle?
If the engine is too cold, that could explain the high air mass.
To assess this value more accurately, it is also necessary to consider the values in Block 1.

The most common causes of the error are usually:
Fuel injection timing valve (N108) defective.
Needle feed mechanism (G80) malfunction.
Fuel tank emptied.
Fuel supply not working correctly.
Fuel shortage.
Funding start not OK.

What can you exclude from that list (besides the G80)?

Thank you for your quick remote diagnosis! I'll give it a try!