dropping fuel economy

[zimwiz1]

Hello everyone,
I am new to the site and am looking for some help with my 99 powerstroke. I purchased it with about 203k on it and have owned it for 2.5 years and now has about 273k on it. When I bought the vehicle, I was getting about 19-18mpg and now I am around 14.5 mpg. This is strange to me because I have put on a cold air intake from volant (about 6 months after purchase)and a stage II eliminator from sp diesel (about 2 years after purchase) to try to increase the economy. Is it possible the cold air intake is robbing effeciency because it is too cold? I run the chip on the efficiency mode and baby the pedal trying to squeeze every mile out of every drop. I thought that I may have injectors going bad but the truck runs fine other than loss of mpgs. I have also unplugged the ebpv because it seemed to be kicking on more often than it used to. I don't know what is up. my goal is to at least get back where I started my journey with the vehicle. Any help is greatly appreciated.
Thanks
Dwayne