How did he adjust the fuel and idle? On the computer?

Didn't think you could adjust the parameters on these.
My nan has one and it's complete sh!te.
Headgasket, waterpumps, coils, various sensors, never wants to start, I can't find the issue, new gaskets everywhere, new lambda, temp sensor, coil, plugs leads, new throttle body and still takes an age to start sometimes. Others it will start fine and be spot on all day, the next takes an age and runs rough. Fuel pressure and compression is always good.

It's not so bad as it won't start and is undrivable, I don't think they notice tbh.
No gearbox issues but it's an auto.