My first D2H experiences....

I received my D2H last week from Cameta. It had a little less than 2000 shots on it and looks like new. I have to admit I am extremely paranoid about focusing/metering problems and I approached the camera expecting it not to work. Saturday we all went to Strasburg PA. to ride the steam train and just enjoy the Amish country side. It was a partly overcast day.
I shoot in aperture priority most of the time. I realize that there is a large learning curve with this camera, but my preliminary results are not as good as what I was getting with my D100. My main complaint is with the high number of out of focus shots that I got. I tried various focus modes and I used matrix metering. On Monday my son and I went to the Philadelphia Zoo to give it another try. It was an overcast and chilly day. I had a lot of trouble with my Nikkor 70-210 not focusing. It would not react at all when I pressed the shutter button. I found if I turned the camera off and back on again it would work for a few minutes. Usually it stopped working if I zoomed from 70 to about 150. By the end of the day it was almost a continuous problem. I tried my Tamron 17-35 and Nikkor 18-70 and they worked fine. Once again when reviewing the shots at least 50% were out of focus. The exposures were right on and definitely better than I got with my D100. Yesterday I tried to duplicate the problem with the focus and I could not get it to happen with any of my lenses in any focus modes. I was wondering if any of you have any words of advice and encouragement to give me as I am extremely disappointed as my main reasons in getting this camera were the improvements in metering (which seems to work) and the improved focusing over the D100.
All help will be appreciated

 

I forgot to add that it doesn't work in single focus but does work in continuous focus when the problem acts up. The same lenses worked perfectly on my D100.

 

Thanks for your input Steve and Frank.
I will try cleaning the contacts again. Like I said I tried the camera and lens yesterday and everything worked fine. Could it be something with the weather conditions when I was shooting? In the 40's and very damp conditions. Yesterday was sunny and 60 degrees and everything seemed alright.