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Ensure fuel pressure is present. Ensure all transmission mounting bolts are present and properly torqued. Ensure there is not excessive end play of the crankshaft. Check by using a pry bar on the crank pulley. Check the connector at the Crankshaft Position Sensor (CKP). Ensure the terminals are tight and fully seated in the connector. Look for any wiring issues going to the connector. Ensure the correct wire is going to the correct terminal of the sensor. With a scope, check output of the CKP. Check while cranking. Watch the pattern as the starter stops spinning. If the pattern looks like it was drawn with a Sharpie (thicker line) or has vertical lines on top of the regular pattern when the starter is engaged and the pattern looks good when it disengages, interference is getting into the CKP signal. Verify wiring for the crank sensor is not near the wiring for the starter. Ensure the wiring back to the Engine Control Module (ECM) is a shielded pair. Interference could possibly cause this problem. Check the tip of the CKP for metal shards, possibly from a bad starter/flywheel ring. Verify there is good power going into the coils when cranking and Key On Engine Off (KOEO). Ensure the ground is good to the top cover; the top cover grounds the ignition coils and a poor ground can cause interference/feedback. Check condition of the battery. Check voltage drops to the starter. Check connection at the jump start terminal under the hood. Check starter amp draw. Normal current will be approx 140-150 amps after inrush at room temperature. See "Related Documents" for a known good current waveform. Disconnect the CKP to insure it is not causing the high current. A bad starter can interfere with the CKP signal. Remove the transmission and check the mating surfaces between the engine and transmission. Use a wire brush or wheel to clean the surfaces.