Help me solve this problem. Scan file and tune file attached. I have replaced every sensor, tried 2 different (0411) PCM's, two sets of injectors and two different wiring harnesses and the problem persists. Engine is a 468 cid LSX tall deck, E85 fuel, Mast split manifold with Wilson throttle body and huge cam on an SD tune installed in a race boat. The problem can be seen in my scan file. Engine held constant at 3200 RPM and it sags below 1000 rpm every 2 to 3 seconds. Everything is properly set up and has been running for more than 3 years with this configuration. I even ran the engine with a Dominator carb using the PCM to run the sparks and it ran fine. This verified the PCM, reluctor wheel, and crank position sensor. I can only figure that something in the tune is causing the problem. This has been killing me for months and I hate failure.