Today I just got home from visiting family and found that my 2004 MCS with apprx. 105,000 mi. will not start. It will turn over and the battery seems alright but it just won't get going. It was driven less than a week ago and didn't have any problems. It's been getting colder, so I did put in a bottle of HEET just in case is was water in the gas line but it's been about 5 hours and no change. The only problem I can think of is fuel related? Ideas for what/how I should check this?