JEP NISSAN TERRANO 1993 problems.

Hello good day I am new here ... Safe to all ....
I am from the city of Punta Arenas, Chile, I have the next problem ..
it is necessary that I was on the road when suddenly a very strong noise was heard and a takateo in the valves, so I am able to make me and start checking unfortunately, it was already night, so at home no more home. The next day I started to disarm the lid and see the valves, but they are impeccable. I began to review the 1st, 2nd, third and fourth cylinder ok injection system ....
I thought it could be an injector the fourth!
Tomorrow, how to clear everything to review the cult, a seat of the valve is damaged .. If someone has an information I would appreciate a lot in advance and I hope to get and share good knowledge on this site .... Cristian, Punta Arenas.