P0203 / P0303 troubles

[Northern96]

Hey all, I'm a novice in need of advice/guidance.

I've got a '96 XJ with the 4.0/AW4 and it has P0203/0303/0300 codes. Between November-January the following (related) parts have been replaced:

-Spark plugs & wires (dist cap Sept '23 but contacts were cleaned)
-Fuel injectors & pigtails
-IAC
-Head gasket
-Fuel filter
-TPS

-Noid light test showed no pulse/no light on the cyl 3 injector connector.
-No resistance measured between injector (yellow/white wire) and PCM (pin 5 on white plug)

At this point, I believe either that wire may be shorted somewhere between the connections, or the PCM isn't sending the ground signal.

*** How do I test the PCM to ensure it is sending the ground pulse correctly to injector 3? ***

I'd like to rule that out before I cut into this harness that has no visible chafing or damage.
Or am I overlooking something else entirely?

Thank you!

 

[Saudade]

Check the positive side for 12v. All injectors should get 12v with the key on.

When you say "no resistance" do you mean essentially Zero ohms (continuity)?

Did you have those codes before the work you listed above?

 

[Northern96]

Check the positive side for 12v. All injectors should get 12v with the key on.

When you say "no resistance" do you mean essentially Zero ohms (continuity)?

Did you have those codes before the work you listed above?

Yes the injectors get 12v, and yes there is continuity on the ground wire of injector 3.

These codes are new.

The only continuous issue I've had since around November was a rough start if I didn't blip the gas while it cranked. I suspected the TPS (not first time I've experienced that issue) but waited until the head gasket was fixed in case that was the cause (it wasn't lol). New TPS and it starts great mostly, just the misfire while running now.