Idle not smooth as it used to be (seems like)

[99FirebirdV6]

so about a month and half ago i had cyl 3 misfire. So I changed the ignition coil for cyl. 3 and it worked fine for one month. Then the problem came back.. cyl 3 misfire. So this time i just went ahead and got all the spark plugs and wires changed.

I had it done on monday and havent had any problem yet. But the engine seems to be little rough when sitting at idle. You could hardly tell but just seems not as smooth as it was before. While running it is smooth and no problems. But at idle engine seems to be shaking more than it was before.

Is it normal or its just in my head? It has 71k mileage on it.

I also changed the pcv valve and the air filter.

[Red]

i have about 43k miles on mine. I had never changed the pcv valve, but when i did recently i noticed a slightly rougher (other people wouldnt notcie) idle and slightly louder exhaust (also changed the exhaust tone slightly to more of a light loping sound). I also noticed more power around 30-40 miles per hour.

Don't know if it's the same for you, but just an idea.