Car turned off while driving

Got a 1987 vw Jetta 1.8
Car has around 200k miles
Manual trans
But still drives well when it would fire up,
3 weeks ago I was driving my car perfectly
fine everything worked perfectly, car
stopped acting weird 2 days after a
mission/long 2 hour drive, while driving
about 30 or 40 mph slowing down coming
to a light car would sound like it wants to
turn off while slowing down or going down
a steep hill, didn't really turn off tho it still
kept running, another 2 days later while
driving on 3rd gear or 2nd or 1st going
30mph or 40 the car would shut off on me
and wouldn't turn on after a coople 10
seconds while driving. Next day it turned
on right up but 10 min later after driving the
car would stall and turn on and off and on
and off like 5 times and backfire also sins I
had it straight pipped, got home turned the
car off and next day wouldn't turn in no
more, would crank but not start, thought it
could be the mass airflow sensor because
it was very dirty and has never been
replaced got a different one from the a all
German junk yard, on the next two days
the car turned on on the second time but
wouldn't rev over 3000rpms and stall,
cranked it again and it turned on and
reeves it slowly till it got up to its max
Rpms idk if that was wrong to do because
after that the car stalled on me and it
wouldn't start up again, and yes I did use
lots of mass air flow sensor cleaner on the
part,
Anyone know what the problem could be?
Is it still the mass air flow ?