My dad has 2012 Mazda B2300, 60K miles. occasionally cranks but doesn't start. Did your Cranks but doesn't start video. Has fuel, spark, etc. Only every once in a while does it crank but not start. Mechanics said they had to see the problem to diagnose it. No codes even with dealer scan tool. Garage said maybe the chip-key system is breaking down. Tried a different key when it didn't start, and still nothing. Garage found old TSB on chip key breakage, but stealership wants $150 to do that repair, and they aren't sure that will fix it.

that's the problem with mazdas, guys often don't know how to fix em right, including at the dealer. Could be the other end of the chip system breaking down too, and only a dealer could figure that out (if they had good enough mechanics which they often don't) good luck