I would definitely put a mechanical gauge on their to confirm the anomaly. That's strange.
I'm not too familiar with the LS1 oil pump, but the LT1s have a pressure relief spring. If the spring gets stuck there's no return to the oil pan and everything is forced into the oil gallies. This can accelerate bearing erosion.
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-Joe-
1995 Trans Am
Advanced Induction 383, Performabuilt 4L60E, Ford 9", all motor, daily driven. 10.82 @ 124.25, 1.43 60' 455whp, 445wtq Clip of 10-second pass.
If your motor has for example, the Melling 10296 HV oil pump with the high pressure spring installed, then yea that would be normal characteristics of your concern. But if it has a stock oil pump, the relief valve might be stuck in the closed position.