Hi, my name is***** your mechanic automotive expert, and I will be happy to assist you today. In some cases, I may need more information to assist better. I apologize for any delay.
I try to be here most weekdays and some weekends. If you respond and I do not respond back right away I will do so as soon as I can.
Dear customer, there are several factors that can affect this kind of failure. I understand that you have already performed a filter service and that you have performed a diagnosis, but the vehicle did not show error codes, so from my position I observed that the vehicle is presenting are problems, obstruction of either the fuel injection system or the air intake system, which is why the vehicle took a moment to recover the rpms and then allow the correct acceleration of the vehicle.
So, according to your description, I am going to recommend two main things.
First, you are going to have to do a thorough maintenance to the injection system, so I recommend that the pump be disassembled as well as the injectors and then checked and calibrated on a test bench, in addition to being cleaned.
On the other hand, the throttle body I also recommend you disassemble it and clean them with carburetor cleaning fluid, for this job you need the VAG software to perform a body calibration, once the throttle body is installed again.
I do not know the mileage of your Audi but it is good that you apply an oil filter replacement to the transmission, although this problem is not directly related to the transmission, it is likely that the transmission still deserves maintenance and it may be that the delay in the transmission acceleration is not from the engine system but rather the transmission is taking a while to assimilate the engine load, this can happen when the transmission oil does not have the proper viscosity and there are pressure problems.
Do you understand me, dear customer?
My goal is to give you the best advise i can, therefore please do not doubt to ask if you have any doubt or if there is anything else i can help you with.
Kind regards, Sebastian.