My car started missing real bad. When stopped at a traffic light or stop sign is would feel like it was going to die and would shake real bad. Yesterday it died at a traffic light. We got it home and replaced the coil pack and plug wires. Now it seems to not be getting fire on the #4 cyclinder. The engine light is on and the miss is worse than ever.

Sounds like the car started to misfire. You should have the car scanned for fault codes. An ignition coil or ignition wire set failure would cause this.

correct thinking
the car has an onboard code reporting system that stores fault codes
have the fault codes read and that will point you to the fault area
all the suggested are not correct because you say that it idles
i'm thinking a faulty brake booster or other serious vacuum leak

Crank shaft sensor.

Spark plugs in your car are good for 100,000 miles. try changing fuel filter and add a can of B&G 44K fuel additive. This stuff is the best on the market and only available at dealerships. It conditions fuel pump and injectors, also absorbs water in fuel (methanol). Try this first, your car is too new for any other problems. this should help drivability and fuel mileage. If Nissan does not have B&G, I know Toyota does. Also stay with 91 octane fuel. Check oil and coolant often. do not risk overheating in traffic, watch your gauges......

Bad coil, fuel pressure regulator or fuel pump. Vacuum leak etc.

I had the same problem with the same model . If it is 3.4 crank balancer shaft is broken.

possible collapsed lifter, timing belt jumped time, check eng light on?

When i'm stopped at a light or sign my cars rpm's go down and my car shakes and sometimes either acts like it wants to die or just dies

you need to replace the fuel sock in the tank and the fuel filte and do a tuneup wires plugs and cap.

Sounds like the EGR valve is bad and is stuck in the open position.Just replace that and you should also check the catalytic converter.