1999 GMC Jimmy • 148,000 miles

I noticed about a month ago that my car is a little louder and feels like it is vibrating more than usual. I only notice it when I get up to about 45 to 55 mph or above. The noise decreases some when I go around a curbs/turns. Not too sure what is causing this. Also, I feel like my mpgs are down some since I started noticing this. I have been using my heater more recently and know that will effect my mpg some. Also, my service engine light will come on for a day or two and then go off for a week or two at a time. Not too sure why it won't continously stay on if something is wrong.
November 27, 2012.

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