I'll be the first to say it. Ignoring CEL's will only eventually lead to more serious (and expensive) CEL's. Have the truck read with a BMW code capable reader. P codes only get you a general idea of the issue.

On cold start does the truck make any weird rattling noises? The original P code for cyl 7 miss might have been the coil and/or plug or even injector. How long have you had the vehicle? Done any maintenance on it?

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)