Okay I've replaced the old sending unit due to the fact I snapped it clean off when I lightly tapped it!
Now I've still got low Oil Pressure though when at idle & when at idle in gear too. In fact it'* so low it sets off the "Check Guages" alarm as well.
There is also a "knock" now that wasn't there before (or if was, it got louder).
This has all happened in the last couple of weeks, since I tore apart the back head to replace that burnt Exhaust Valve.
I was thinking maybe the Oil Pump in the Front Cover? Oil Pressure Relief Valve sticking? Something else, as the engine comes up to normal engine temperature the Oil Pressure lowers!
One thing I've changed in the last two weeks was the Oil & filter. I switched from Mobil 1 10W30 Synthetic & AC Delco (PF-47) Oil Filter over to AMSOIL'* Full Synthetic 10W30 Oil & AMSOIL'* Super Duty Oil Filter. Could the AMSOIL be slippery
than the Mobil 1 was? I do know that AMSOIL has less friction than Mobil 1 could this be my problem? If the Oil Pump was weak before, but not as noticeable due to the Mobil 1 in the engine, but when I switched it over the an even better Oil could the weak Oil Pump be not able to keep the Oil Pressure up with this type of Oil? I've seen it before on old, tired engines, but never on a 3800 yet.