I'll be glad to help you to do this work yourself; but in exchange I ask that you trust my experience and do ALL the things I suggested, rather than only doing what seems likely to you to be the cause of the problem. Believe me; every one of those things could cause it, and sometimes it is caused by combinations of factors, rather than there being just one cause.
There are two different chemicals need to do this job properly. One is called throttle body cleaner, and the other is called mass airflow sensor cleaner. The mass airflow sensor can be damaged by using anything except mass airflow sensor cleaner on it.
The mass airflow sensor is located in the air duct from the air filter housing to the throttle body. Here's a link to a photo:
/...). Disconnect the hose from the sensor, and spray the inside of the sensor bore with mass airflow sensor cleaner until the sensor wires are clean and shiny. Do not touch or scrape the sensor wires with anything. Just spray them.
The idle air control valve is mounted on the throttle body (http://www.rockauto.com/catalog/moreinf
o...) with two bolts and has an electrical plug connected to it. Remove the bolts and take the valve off. Spray throttle body cleaner into the opening where the valve attaches, and clean the metal tip of the valve.
Disconnect the air duct hose from the throttle body, and spray throttle body cleaner all over the throttle butterfly and into every opening and passage. Take particular care to clean both sides of the throttle butterfly, and to remove all deposits from the bore near where the edges of the butterfly touch.
If you decide to replace the spark plugs, and would like a recommendation about brand and model; please post the engine model (or the 8th digit of the VIN) and I'll reply with a plug recommendation.