you don't need an sd card to go back to stock, you need the zte warp update tool by zte, it's not up on their site right now but I believe you can find it in the ultimate warp drive thread. before you do that though, you would use adb to push the stock recovery back to the phone
I believe that files is also included in the ultimate warp drive zip, if it's not pm me or look around the forum for it.
steps would be:
download: ultimate warp drive, stock recovery, zte warp handset update tool
enable usb debugging on the phone in settings/applications/development/usb debugging, connect phone to usb
from a command prompt on your computer in the unzipped ultimate warp drive folder you would find the name of the stock recovery image (something like stockrecovery.img) and type adb reboot bootloader
after phone boots to green android picture, type fastboot flash recovery stockrecovery.img (or whatever name it has)
once it says it's complete, type fastboot reboot
the phone will boot, hold the power button and shut down the phone
now hold the power button and volume down until ftm is shown on the screen
now run the zte warp handset update program and follow the instructions to return the phone to stock
after the phone boots up, enable usb debugging and use the ultimate warp drive again to install cwm recovery and check if that solved the issue.