have you checked the spark plugs and wires? if not try replacing those... my 95 eagle talon did about what yours is and I just replaced the plugs and wires and it runs like a top (with over 200,000mi on it!)
The idle speed depends on the year model. The GTs from 1993 to 1995 should have idles speed between 650 and 800rpm. I believe the 1996 and 1997 models had a slightly different idle speed, but either way 1500 sounds too much. You can adjust idle speed on your car of course.