Sounds like you have a broken speedometer driven gear, about $30 from a
dealer. It is a simple part to replace, with the only needed tool being a
10mm socket to remove the outer part of the sending unit, located on the
passenger side of the trans. It is an electric sending unit, so just look
for the wire harness connection just ahead of the forward U-joint. When you
remove the 10mm bolt the inner part is a nylon gear on a post which you will
probably notice has several teeth missing. Just replace that part and not
the entire sending unit, which costs considerably more. When my speedometer
went out, I kept having stalling problems because the computer was not
receiving the correct speed signal from the sending unit. Don't know if
replacing the gear will fix your stalling problem, but it did mine. Good
luck.

hey, i am having the same problem with my 95 rodeo too the speedometer just
stopped working while i was driving it and the check engine light came on.
it hasn't stalled yet on me but i haven't driven it since then. my husband
is going to do everything that you did and hopefully it will work for us
too. i just wanted to let you know that it isn't an isolated incident.
anyways. you havning your problem was helpful to us figureing out what to
try before we pay an arm and a leg for a 30 dollar part we can fix
ourselves. so thank you and i will let you know if it works for us too.
Brittany