code 1238 problem
 

I got a code of 1238 on my 2000 s80 t6 (turbo). I had just changed my coils and spark plugs out and found that after driving 20 miles that I had not connected the front air tube. Of course the car missed, and the idle fluxuated up and down, even cutting off sometime. The code didn't come up until after I found the problem and tighten the hose back. Why was it so late, and even after I cleared the code with my code reader it came right back. Do I need to dis-connect the battery or did I damage something. Also I am weiry of my plug gaps. They were surpose to be pre-gapped and some of them were not. Could a bad plug gap cause this? I did use bosh platnum plugs.