info: 2006 grand prix 3.8l 6 cyl

Worked fine until it just wouldn't start. Turns over, all electric good, just no spark.

Error codes:

p020X x being 1-6 -> injector circuit open cylinder X
p0030 ho2s heater control circuit (bank 1, sensor 1)
p0036 ho2s heater control circuit (bank 1, sensor 2)
p0443 evaporative emission system purge control valve circuit

Thought it was a fuel problem but spraying starter fluid into air intake produced no results.
Changed ignition control module without effect.
Thought it was either crank shaft or camshaft sensor.
Turned it into a mechanic to change those.
After the mechanic had it for four weeks, it is still the same.
He replaced the computer (reprogrammed for key), load center (fuse box under hood), oil pressure sensor (new code error that randomly comes back), crank sensor, cam sensor.
Thankfully he has a "if I can't fix it, I wont charge you" policy. However, we are still where we were.

Checked voltage to pink wire at each injector. Results is 4 volts at each.

Any ideas?

Same Codes as before