My friend who currents owns an s12 can not get it started, we tried everything. At first we thought it was just the battery then we thought it was the alternator cause we have been thru 3 batteries,so we took the alternator to advanced auto parts to test it and they said it was fine,but then we were looking around to find the obvious and we saw that an injecter was leaking,but the engine still gets fuel.So I really dont know now.