What do you owe the person that buys your car?

As you state, a used car is sold "as is". You are required to tell the buyer if there is a brand on the title, for salvage/rebuilt. Other than that, you are not required to disclose any problems, if you can live with yourself after hiding serious issues, then do that. The buyer must make a reasonable decision, if they are not familiar with cars, then they should have someone with them, that is. Remember the effect karma has on your life.

you owe them clear title to the car. Nothing more.

Unless you made some sort of promise regarding quality, history, extra service, or some form of guarantee (in writing or in front of a credible witness), you have no further obligation to the buyer.

Part of the reason that used cars are so cheap compared to new ones is that it is impossible for the buyer to know if they are getting a lemon or a peach...in other words, it's a bit of a gamble. Peaches rarely get sold and most used cars are thus lemons.

If you deliberately misrepresented the car, however, that is fraud, and you may be liable for civil or criminal penalties (like for instance, you said it had a new engine, when it didn't, or you said it had never been in a wreck, when it had, etc.). If you didn't make any claims, and truly just sold it as it was, then caveat emptor.

Honesty and integrity.

There is no way of you knowing the transmission may work well until the car is junked or whether or not it will require major repairs next week.,you have no way of knowing.If the engine blows next wek, how could you anticipate that?

But if you just got it inspected, and the front end needs major work, and the mechanic says "it's an accident waiting to happen" and you hurry up to unload it,

I don't think that is an ethical thing to do if you conceal that fact from the buyer.

NO. The vehicle is "AS IS". BUT you should feel guilty for doing that to someone! You do not owe the person anything except for maybe letting them know you were very poor at keeping service up on the vehicle so they might be able to service it before any other damage is done.

If the car was sold "as is" and the buyer knows that, you owe them nothing. If there is something wrong with the car, it is their fault to not have it properly inspected before purchasing the vehicle. You did your part, they didn't do their's properly. Hope this helps!

NO> if someone is fool enough to a buy without checking it out deserves what they get.

some simple human courtesy would be nice!