Hey, I know exactly what you mean. I had the same thing with my 2012 Toyota Auris. My mechanic said it was damage to the wiring harness. The symptoms were almost exactly the same: deteriorating engine performance, high fuel consumption, engine jerking when accelerating and even idling. It turned out that the problem was caused by a number of defective cables and connectors. The repair was a certain level of seriousness because they had to replace the entire wiring harness, but after the repair my car ran like new again. I can advise you to go to a mechanic you trust and have the fault memory read out before you decide on a mass air flow sensor. It could also be a cable problem. Hope this helps you! Greetings!

(Translated from German)

Hey, thanks for the quick reply! The wiring harness sounds pretty bad, I'm glad your car ran smoothly again afterwards. Do you remember how much it cost you to replace the whole wiring harness? And have any similar problems occurred again since the repair, or was the issue closed for you afterwards? Thanks again for your help! Greetings back!

(Translated from German)

Hey, no problem, helping is a matter of course. I paid the mechanic around €95 to repair the damage to the wiring harness. I have to say that the bike ran like new again afterwards. And to come back to your question: After the visit to the mechanic, the defect in the mass air flow sensor was fixed. So, no further similar problems since then. I was quite relieved that the issue was closed for me after that. Hope it goes as smoothly for you. Greetings and good luck!

(Translated from German)

Many thanks for the detailed information. That helped me a lot! 95 sounds really bearable if the car runs like new again afterwards. It's reassuring to hear that you didn't have any further problems after the repair. I think I'll start looking for a reliable mechanic and hope that it can be fixed similarly easily. Thanks again for the advice! Greetings back and have a nice day!

(Translated from German)