88 civic wagon surging/stalling
 

My 88 honda civic wagon surges intermittently( feels like the car is
rocking back and forth rythmnically like a heart beat every second when
at around 1500 rpm at lower speeds) and recently began stalling at
highway speeds. I can go a full 2 hour drive and not have a surge, or
at least not one that I notice,or a stall but then it will act up.

When it stalls out it will sometimes start right away and keep running
but more often will stall back out. Sometimes it wont start at all
after its stalled. The fuel pump was not turning on after the stalls. I
took it to the mechanics and they checked fuel pressure, Checked IAC,
checked for vacume leak, replaced the fuel filter, o2 sensor, air
filter, fuel pump, fuel pump relay,cleaned the throttle body and
disrtibutor and checked/cleaned the fuel injector.

It still is surging and I don't want to go through the scare of taking
it back on the HWY to see if it will stall.

My mechanic is at a loss. Anyone have any ideas? I just bought this car
used a month ago and already spent a wad of cash trying to get this
issue fixed.

Thanks for any advice/help