I ran mine capped off for one day. I had a mental lapse and deleted it the day before I did my JPC breather kit install...thinking it was part of the pcv. Somehow I got it in my head it connected to the pcv which it does not of course. I guess I'm getting older? Anyway, someone pointed it out after I posted a pic of the results and right after they did I thought to myself "Why did I do that?". I drove it for a day like that. I didn't notice any changes in shifting behavior.
Actually my laymay's thinking on the engineering reason...Possibly due to different TB closing rates on the manual or automatic and pressure changes between the intake pcv hose and CAI side of the hose?? Pure guess. Something to do with the brakes I'm thinking as there is no sensor in between the CAI fitting and the upper intake manifold, or the brake booster.
'14 Race Red GT M6, premium, comfort package, Steeda stb