My 2008 LMM lit the service engine light last evening and when I read the codes it indicates the glow plug for cylinder 7 has failed. I reset the code and it has not returned for several starts now. Does this make any sense. I have not read the resistance of the number 7 glow plug yet- plans to do so later today. Engine only has 78,000 miles on it. The Weather has been in the high 90's the past few days and I have been doing a lot of high speed driving and a fair amount of idling to stay cool, wonder if this has had any affect on the glow plugs or associated electronics