Really need some help on this one from some of you sonic experts. My sonic( I know this is a cruze forum, but I'm looking for help anywhere I can get it considering its the same 1.4L engine) has a hunting idle. Maybe 25-35 rpm, but its noticeable, I just replaced the intake manifold which cleared it up alot, the red check valve had come out of the original one, once I installed the new manifold it cleared up quite a bit, but still there. I'm an ex tech, but sold my nice snap on scanner, so I dont have the ability to diagnose this thoroughly, I just have a cheapo scanner, which nothing shows out of the ordinary. I also just notice that at idle sometimes my mph shows 1 instead of 0, do you think a faulty vehicle speed sensor could be affecting the idle condition? I'm not sure if this would affect the can bus network GM uses. The car has 130,000 miles on it so i know at that point it could be anything, but I' getting normal scanner readings, no check engine light, and drive ability is fine. Any input would be great.