I have a 2012 1.4 Turbo cruze. I got it from a dealership with 90K miles on it and it was great. I got to 100k miles and started getting lean codes and other air intake related codes. I found the PCV valve in the valve cover to be bad, I replaced it, and car did great! I got to 108,500 miles and did my routine service, but I decided to change the factory spark plugs out. The car ran great! I drive 115 miles a day and use cruise control for 90% of it, even on the hills and roads. 350 miles or so after the oil change/spark plug change I noticed when the car would downshift to go up a hill it would surge once a second or two after the downshift. I brushed it off. As I got to 110k miles the car began to surge more often. Any time the car would downshift around 1/3 throttle the car would surge repeatedly. I could let off and it would stop. I chose to stay in the throttle a time or two and the car would flash a check engine light for maybe 15 seconds and it would go away. It would also bring up the stabiltrac logo and say service stabiltrac and service ABS. I decided to take it to the dealership and they said the car had random misfire and lean codes, along with an ABS code. They said the ABS code was possibly fixed by a PSB out currently which just called for a reflash. The lean codes were pinpointed to a "massive" vacuum leak, apparently the intake manifold gave way. Now, $725 later the car is still surging. I've seen multiple complaints on consumer websites with this issue but I've yet to see any answers. Has anybody else had this issue and found an actual problem? I don't want to waste more money at a dealership. Thanks to any insight.