I'd try adding some transmission fluid to the oil to maybe free up a sticky lifter.
You couldn't just swap out a crank/pistons/rods without costing yourself 1000-1500 in machine work. You could buy 3 used motors for that price. Rebuilt 3800's never last.
Lol you guys that say rebuilt 3800's never last is about the dumbest thing ever.... It's a motor it has nothing to do with it being a 3800 if you don't have a retard build it then you shouldn't have any issues.
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00 Grand Prix GT, top swapped, .020 FMP, GT1 Cam, SFI Crank pulley, SSM90, 3.3 MPS, ZZP ported Gen 3/LIM, ported heads, #90's, N* TB, SLP Intake/Headers/Catback, F-body brakes, KYB AGX, Aeroforce, AEM, 93 octane.