Lean Condition

96 Civic HX with 96 Civic EX motor and
transmission. System started running lean
after I started parking my car differently (on
an incline with front end being on the upper
and rear end on the bottom of the incline).
After a month of parking like this at my new
job, my car started throwing check engine
lights. It was the lean code so I got a injector
rebuild kit for St but to no avail, I got 4 new
injectors, fuel filter, air filter, spark plugs,
plug wires, oil change, and oil filter but all to
no avail. I replaced the PCV valve and hose (
another oil change because of the location
of the PCV valve). Checked fuel pressure
with and without vacuum and it was within
specs, checked for vacuum leaks ( with
starting fluid) but no change and no leaks.
Fuel pump is working but could be weak,
fuel pressure regulator is working, now the
only thing left is either a weak fuel pump,
Oxygen sensor, or the HX injectors are too
low pressure for EX setup. I didn't think EX
vs. HX would matter until I got a fuel
pressure regulator for an HX and it would
not seal to the fuel rail and the vacuum tip
was straight instead of bent. I checked the
part numbers for the regulators for both
models and they were different, so I checked
the part numbers for the Injectors and they
were different too. Car was swapped from
automatic HX to 5 speed EX. No Catalytic
converter and no map sensor ( never had a
problem with those two things missing in
the 4 years I had the car. So with all that
being said, Can HX injectors cause lean
conditions ( check engine light) in an EX
motor/ fuel rail/setup?