1999 chevrolet truck rough ide .wont keep running?

I asked this question earlier, but most found it a better answer to comment on original messages typos (misspelling) and not read the message for what it meant. simple question here goes>> what would cause oil to seep in along throttle body (upper left corner) of a 1999 chevrolet silverado..most said take it to a mechanic.. in not so kind words. lets see 100.00 later after being to a mechanics there best answer was change all 8 injectors at 250.00 per just the cost of a injector. now even i know all 8 injectors dont go bad at once.pulled the injector bars and all seemed fine from what i could tell. again I stated seeing a white substance oozing into throttle body which with check engine oil level light would make me ume possible oil substance. Hope THIS spelling helps those who didnt understand question first time. (note laptop spelling at 2am can cause typos,, sorry)