I have this weird behavior on my car. It began with the rpms going down and up occasionally and sometimes stalling. After some resarch I tought it cloud be the throttle body so I cleaned it and replaced the air filter but it didn't fix it. It has an error in the PCM the code is 443. This is an evap valve failure.
Also took it to the workshop. They told me this code is not the cause of the rpms misbehaving. There they cleaned the MAF and checked the gasoline presure and calibrated the PCM but still the same problem.
At this point I started to realize this weird thing. At speeds like 40Km/h. When I'm slowing down the rpms only misbehave when I don't push the break pedal or push it too little and most likely it will stall. If I push it enough it's like the problem doesn't exist.
Then I took it to a second shop. There they found the alternator was throwing too much voltage. So they repaced it. Now the problem is not that big but still it is stalling. So I think there's a componenet that was burned by the alternator. But the only code it has is 443.
If it were a malfunctioning component should it throw a error code right?
Which systems operate in this scenario? throttle body? transmission? can the evap valve be responsible of this?