Okay, take a look at the picture and you can see the crank sensor wiring.
Brown goes to ground, yellow is the bias voltage from the computer and the black wire is the signal.
Use a volt/ohm meter and check if you have a good ground on the brown lead, Then see if you also have good power feed on the yellow. (Should be either five volts or battery voltage). If either one is missing or wrong it could cause the sensor to misread.
Beyond that you could use an oscilloscope to look at the actual crank signal. And possibly pull the sensor and look inside to see if the lobes are okay on the crankshaft.
If those look okay then you would want to have the ECM checked as it controls the ignition.
Image (Click to make bigger)
Friday, February 19th, 2021 AT 1:48 PM