Thanks some guys this forum, I found my problem was a leaky injector. I've called Nissan here in Colombia and they tell me these are known as O-ring. It have to be import from Japan and are very expensive. My questions are: are there 2 O-rings type in each injector, or am I supposed to find what type is mine? can I change these isolators easily by myself? is there something I can do for stop this leaking while I wait for them (they ares supposed to arrive in about a month)?

Thanks a lot for your patience. I know they are a lot of questions, I'm thankfull for your answers. In my country not even Nissan know a lot about this engine. Ooops :biggthump , my engine is a SR20DE highport. Sorry about my non-perfect english.

look those guys dont know what they are talking about.. those orings can be had from Home Depot (local hardware store) for less than $1 each. There are two orings but the one you need is the bottom one

How can I know what is the bottom one at Home Sentry or Home Depot? how can I get those there? they are supposed to be called o-rings?

the seals should cross over to a part number on some kind of car they sell down there, do not use the Home Depot seals, they are made for water and such, not gas, they will break down and leak eventually...

each o-ring costs about U$15.