I have a 2009 Malibu LTZ with the 3.6L motor. At the beginning of the year it went from my daily driver to a spare that my children will drive. I let it sit for a couple months and had to replace the battery and no I drive the car on my days off but this car has caused almost no problems for me. Recently it developed an exhaust leak on the flex for the front cat converter pipe, no big problem there is no emission testing in my county. Then the car started to idle poorly after it warms up and now throws the engine light on. I could feel a misfire in the idle and since the car had 135k miles on it I bought new plugs and coil packs. I still get the rough idle but no misfire and the engine light still comes on. I used a blue driver and the codes I get from the car are U0073, P0700, U2107, U2106 and U2105. I wondered if anyone else had this experience and how to deal with it as the codes talk about 3 different modules and before I get the parts cannon ready I would appreciate any help. The suggestions have both replacing the modules or wiring harnesses and I am wondering if there is a common thread between them that could cause these issues.