MY FX SOMETIMES DOESNT START ON THE FIRST CRANK BUT STARTS ON THE 2ND

Some models of Nissan/Infinity have a known issue with the fuel pump drain back valve (it leaks). When the valve malfunctions, the first time you turn the key to "start", instead of fuel being at the engine already, fuel needs time to get to the engine. Which is why it starts on the second try. (the drain back valve normally keeps fuel in the line so that this doesn't happen. To diagnose: ****allow car to sit unused for a few hours before trying this, overnight if possible*** 1. Turn key to "ON" position for 5 seconds, (the position right before the engine cranks) 2. Turn key to "off" position for 5 seconds 3. Repeat steps 1 and 2, two or three times before you turn the key to the "start" position and crank the engine. (this ON/OFF key cycle is triggering the fuel pump to run, in an effort to prime the lines with fuel) 4. Attempt to start the engine normally. If the engine runs, you most likely have either a bad drain back valve, or leaky injector(s). If you properly complete this test, and the engine still doesn't start the first time (on step 4), then some other issue is more likely to be the cause. If your model has a push button start, you'll want to push the button in such a way as to turn all the vehicle electronics ON WITHOUT STARTING the vehicle, and then push the button again to turn off all the electronics. This will be the equivalent of performing "key cycling" as described in the step by step. Hope this helps :)