1999 Dodge Intrepid

Engine Performance problem
1999 Dodge Intrepid 6 cyl Front Wheel Drive Automatic 151000 miles

When I crank up my car, it starts misfiring if I turn on the rear window defrost it doesnt do quite as bad. The tachometer is all over the place up and down. Could it be the MAP sensor or knock sensor or what. Can someone help me please.
October 28, 2010.

Engine running rough or misfiring can be cause by the following: 1. Defective spark plug
2. Inadequate spark/coil, defective spark plug wire.
3. Lack of compression
4. False air leakage.
5. Faulty fuel injectors.
6. Insufficient fuel pressure.
7. Contaminated fuel.
8. EGR valve that is leaking.
9. Oxygen sensors.
10. Throttle position sensor.
11. Manifold absolute pressure sensor
12. Idle air control motor

Oct 28, 2010.
I changed all coils, plugs TPS, IAC, Crank sensor, cam sensor, oxygen sensors, pcv, i'm stumped. Please help me.

Oct 28, 2010.