1997 Dodge Intrepid High Idle and Trouble Codes

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1997 Dodge Intrepid 6 cyl Wheel Drive Type unknown Automatic 114000 miles

Hey Everyone,
I have a 1997 Dodge Intrepid, V-6, 3.5 L with about 114,000 miles on it. The car was parked for about six months without being started. Now, when I start the car the idle is very high. When I drive it, it will accelerate to 40 mph without me having to give it any gas. The check engine light is on and is giving four codes-12, 25, 27 and 43. Are these all related to the high idle? Is it safe for me to continue driving the car until I have a chance to get it in the shop? Are these expensive repairs? I have a Haynes manual and a little bit of know-how i.E oil change, tune up, etc). Is this something I can attempt myself? I would appreciate any advice! Thanks!