Nissan Repair: Hardbody 4x4 2003 model Cranks but wont start, neutral safety switch, test light

Question
When i turn the ignition key it cranks once i release it the engine stops

Answer
Bulane,

The ignition is comprised of a start and run mode.  When you turn the engine over the starter applies along with current to the ignition.  Once the ignition springs back to run another circuit takes over.  I would check the coils to see if there is power when you are in the start mode.  I would think the ignition switch, power feed to the coil(s) or an improperly wired aftermarket alarm system could be the causes.  The only way to know is get a test light and start back tracking from the coil to the ignition switch.  The fact that it turns over means the neutral safety switch is not the problem.