Cristian,

Mate, the only way you will fix this problem is through trial and error, or more simply put, swapping out parts one at a time as ben73 has suggested..

If you have a different radio, ESC, servo that you know works, then change them over one at a time and try it.. What have you got to loose...?

One more thing.. Try removing the covers from the ESC and receiver and clean them out, especially if you race on carpet.. It may be something as simple as a small stone / piece of dirt rolling around inside the case shorting things out on the bottom of the PCB..