Hey,
I just replaced my starter (got the new one from advance auto) and it's still staying engaged too long- when I let off the key, it's still engaged. I know what I'm doing, but I'm thinking I may be missing a ground wire. The only wires on the starter is the on wire on the top most stud, and the wire that's got a sensor on the end. Does the bottom of the 2 studs have anything attached to it, cause mine didn't/doesn't. THANKS!

 

Is your ignition spring the key back to the ON position from START? I had a car that you had to remember to turn the key back after it started.

You may also have a defective starter. You can check by taking the starter out, put it in a bench vice and run power directly to it and see what it does.

 

starter's good, car starts up fine. and the key pops outta "start" to "on" no problem