I have a 2004 Chevy Cavalier that I am hoping to sell very soon, however, There's a problem with the engine. What was happening was at first, it felt like it wasn't shifting from first, but then as the summer went on, the RPMs would max at 1500, at the time I was getting an engine misfire code.

I replaced the spark plugs and it got rid of the code. But then the RPMs seemed to get worse. Teetering between 1000-1500 when floored. I then replaced the coil pack, and then the ignition control. Still no improvement, and now the engine stalls.

Cars are the one thing I don't really have much experience doing.

Any advice would be great, I would like not to have to sink any more money into it since I just bought a newer, better car, and if you think I can easily sell "As Is" if I know exactly what the issue is and about how much I could get for it.