I got this code right before I put my car away for the winter last year and again just after I got it out in the spring. Now that it's getting colder it just threw the code again after going all summer without a problem. When the car idles it vibrates a little but the RPM's are real steady and it runs good. What could cause this only in colder weather. I would think a bad EGR would do it in any weather and it's really not that cold ,around 45-50 degrees. A Vacuum leak possibly? if so any ideas how to find it?