1995 Pontiac Bonneville Stalls and systems monitor dings

I have a 1995 Bonneville, have done alot of work on it. Recently the plenum cracked and leaked coolant into my motor and also was coming out of my air intake tube, replaced the plenum and head gaskets (just incase), after that it was running great, a few months later it started stalling out on me, It does it at idle and while driving and the systems monitor dings right when it stalls, 99% of the time it starts right back up, but a few times it took a while before it started again. I found some vacuum hoses that were in terrible shape and replaced them, have replaced the fuel filter, and fuel pump. It does'nt do it as often now, but it still does it, sometimes it does it two days in a row, sometimes it does it two weeks apart, but regardless it's still doing it. Since coolant was coming out of the air intake tube and there are several sensor located on that housing, including the MAF sensor, I was thinking maybe the coolant contaminated those sensors and they are failing? Any ideas?