Stalling issues

OK I have a 2001 Hyundai elantra 2.0 L automatic.
My brother in law had it and just got tired of fooling
with it it runs great except when it just like shuts
off going down the hwy. The is no hesitation at idle
nor any warning signs it's gonna do it, no jerking
like its starving for gas, no spitting or sputtering. Ur
going down the hwy 60-70 or at any speed and it's
like u slammed on the breaks (over exaggerated)
but u can take ur foot off the gas pedal and press it
again immediately again and it just goes on like it
never happened. It only dies if u continue to try to
make it take gas. The chk engine light comes on
and stays on chkd the codes said it was speed
sensor. Bought those but  they came with wiring
harness (decided didn't want to have to retract and
buy that to if the sensors didn't fix it) however I
count find where to plug the end that doesn't go
into transmission without taking all the wiring out
of harnesses. Either way I've cleared the codes and
ran 2 cans if seafoam thru it to make sure it's clean
inside. But to no avail it's worse than ever now. The
sec time I did the codes it gave 7 different things
wrong with it. None of which made sense. Is they
anyone else having this issue. It has slot if miles
on it but runs like a scalded dog.