I bought a MES 40 back in January and used a few times with some success. Today I decided to do some pulled pork. Started it at 9am this morning and it's is now currently in the oven at 8pm at night to finish heating. It seems no matter what I did today I couldn't get a consistent temp. I watched it go from mid 230's to low 200's repeatedly. I will say it was cold and outside temps were around 35-36 most the day and I run with the vent wide open. The Probe is also way off. It was reading 191 when I pulled the pork, my Digital Themo says it was 165ish. I know I'm going to call Masterbuilt tomorrow to see what can be done before the warranty expires. Anything I can look for in advance?