2000 Malibu gauges and warning lights acting crazy.

2000 Chevy Malibu 3.1L
3 weeks ago i was driving and the
car stalled and would not restart. It
would not even turn over.  Finally
found out the starter was bad but
that didn't explain it stalling. I
replaced the starter and now I can
start the car and drive it but now the
abs light, brake light and theft
system light will all come on. (Theft
system light doesn't come on each
time) the abs light and brake light will
come on and stay on until I kill the
car. The theft system light usually
goes out on its own. Also my fuel
gauge will read the proper amount of
fuel then suddenly drop to empty
and my temperature gauge will also
drop. They stay down a few seconds
and then return to normal. The other
day it did this 26 times in 14 minutes.
I replaced the ignition switch and it is
still doing the same thing.
Any help on this would be greatly
appreciated.