Car idles high when turned on?

[Tyler]

ok this is wierd, my 97 saturn sl1, when you start it (it takes longer than normal to start now) it goes up to 3000 rpm then goes down super slow, and it stays above 1000 rpm, and when you put your foot on the brake and put it in either "d" or "r" it like still stays above 1000 rpm and when you let you let go of the brake why it is in "d" or "r" it takes off fast, and after you take off in it and you put it in park, it goes up to 3000 rpm then goes down Again, very slowly! also check engine light is on, and does flash sometimes, when it flash's t starts goin down low rpms and shakes, thank you, also im about to get ready to go to the junk yard so please tell me some stuff i need to get, im goin to get a coil pack and the spark plug wires, thanks