[lawn]

This is a bad idea because the risk of fire is very high. The electrical wires aren't built for the high load of charging a car, and doubly so if they happen to be old. That's why electricians should always draw completely new wires, to make sure that everything is fresh and able to handle the load.

That it's been working for you for a few years does not invalidate this point, in the same way as not wearing a seat belt is unsafe.

[natch]

Yes always use higher spec outlets made for heavy duty appliances, such as kitchen outlets. And yes it's a good idea to get your setup checked, and upgraded or repaired if necessary.