mid print with SD card stops (2 replies)

Hello,

I have a strange problem that start happening only 2 days ago, when i print using a sd card the print stop randomly. If i print using usb and prontoface all goes well, no problem.
the print stop printing because the ramps make a reset, I can see in the lcd the rebooting process. The hotend and bed goes to zero ºC, and the nozzle stay in the last instruction of the print.
In the paste i already make a lots of prints using the sd card and lcd with the sd reader, never have a problem util now.

Testes and conclusion i have already made:
-The lcd module is not directly connected to the printer, is not a vibration issue.
-The ramps and mega do not have overeating problems.
-When i printing from SD card the usb cable is not connected to the pc.
-Already formated the sd card fat 32 and problem still happens
-I do not have a second sd card, not sure if is a faulty sd card.

Hardware:
-the SD card is a kingston sdhc class 4.
-ramps1.4 and mega 2560
-lcd 20x4 ( [createc3d.com] )

Can some one have any clue what can be the problem?