Some days ago, the cylinder head was serviced and the valves adjusted, because my car had an oil leakage that damaged the air sensor. At the same time, almost all the sensors were cleaned. However, it now happens that, when starting to drive, the vehicle suddenly stalls. The fuel pump has been checked and it seems to be alright. But the failure is still there and I do not know what else to check. Could you please give me your opinion?

Hello, my car's problems are the following:
1) the over drive light on the dashboard blinks, and when I accelerate the vehicle it feels slow and it is hard for it to develop high speeds. I do not know if this has to do with a worn gearbox or a damaged sensor.
2) the car is unstable, revolutions raise and drop. Even though this is a subtle failure and it is not audible, it can be perceived when I turn on the lights, as they blink continuously.

My vehicle has got automatic transmission and, when driving to a hilly place with the air conditioning on, it comes a moment when the car starts jerking until it chokes and stops working. I need to leave it off for around 20 minutes and it then keeps working as if nothing had happened. One of the worst things is that it does not consume coolant, the engine temperature does not raise and the check engine light does not turn on either. Might it be a sensor that is failing? This has occurred to me even when injectors were just cleaned, it had new spark plugs and had just been tuned up.