Pontiac Repair: wont idle, chevron techron fuel system, engine sensors

Question
QUESTION: i have a 05 pontiac grand am. a while back it got to where it wouldnt idle, you had to hold the brake and keep the rpms up when you stopped or else it would die, and had to gas it to start it.  i was layed off so had to park it. i would crank it and run it every once in a while. after about a month it just started idling right. drove it for a couple of days and it stopped idling again. parked it again and the other day it started idling again. car has been parked about 6 mo total w/ me driving it up the road every once in a while just to keep it from setting.  any ideas what might cause this.  thanks

ANSWER: Hi Joseph:

what engine is in this 4 or 6 cylinder? Has any service engien soon lamp come on while this was happening?

---------- FOLLOW-UP ----------

QUESTION: sorry about that, its a 6 cylinder and no the service light has not been on.

Answer
Okay lets starts from scratch. Disconnect the battery and clean the throttle body. if the throttle body is really dirty from a carbon build up the engien will not want to idle correctly. once you clean the throttle body out real good reconnect the battery. turn the key to the run position and leave it on for 30 seconds. tune the key off and let it sit 1 minute. then start the car up You may have to hold you foot on the pedal a bit to keep it running due to all the cleaning agen in the engine from cleaning the throttle body. also try a bottle of chevron Techron fuel system cleaner in the gas tank. That should di it if it's just a dirty throttle plate/body. You could have other issues like one of the engine sensors reading incorretly but the basics are easily overlooked.. That is where I would start. good luck :)