Intermittent crank but don't start

I'd really need to know if it cranks OK. If it cranks but won't fire, I'd suspect the EFI main relay of sticking. Take that out and tap it, then replace.

If it won't crank, and then does, I think the main contacts at the bottom of the starter solenoid are worn out. Intermittent operation is typical of that.

don\'t understand: cranks fast enough (battery low??) or crank at all??. Need more detail(s);if it cranks at all but slow,you won\'t get a spark;don\'t touch the end of the spark plug wire \'cause it\'d make your butt pucker if/when you get spark!!! honestly.

Probably intermittent throttle position sensor.

Check fuses first, but could be needs new CPU

Does it crank, yet not start? Or does it not even crank?
If it cranks and doesn't start, you could have a leaky fuel injector. Pull the plugs when this happens, and check them for fuel saturation.

If it doesn't even crank, it could be an intermittent starter.

Cam Position Sensor could be your problem.

intermittent no start situations generally appear when you have defective crank position sensor (since it cant get idea what the crank angle is) and fuel pump issues( since it cant receive enough fuel)

When you say it won't start, do you mean it cranks but won't fire, or it just won't crank? If it just won't crank, you could be having an issue with the starter relay. The often become intermittent before failure. Many owners do not know there is a starter relay because it was added as a recall item i order to protect the iginition switch from burnout. The starter relay is located in the very front of the engine compartment, just to the left of the battery, on the back side of the radiator crossmember.

CODE PO131 - HO2S 11 BANK 1 SENSOR SENSOR I CIRCUIT LOW INPUT CONDITIONS. POSSIBLE CAUSES LOOK FOR INTAKE LEAKS IN THE EXHAUST SYSTEM, LOOK FOR INTAKE VACUUM LINES LEAKS. FUEL SYSTEM TOO LEAN WEAK FUEL PRESSURE CLOGGED FUEL FILTER,WEAK FUEL PUMP. FAULTY HO2S SENSOR.OR HO2S SENSOR SIGNAL CIRCUIT SHORTED TO SENSOR. HO2S SENSOR DAMAGED CRACKED OR HOLE CLOGGED. PCM HAS FAILED.

the crank sensor is behind the crank pulley and must pull off the pulley to gain access to it and it must have the air gap set so the timing slots don`t hit it when the motor is running,this can cause your problem also if the wires rub through by the crank pulley can cause it as well.you say you don`t hear the fuel pump running when it won`t start then you need to make sure that is what is happening as this will cause an intermittent no start(pump works sometimes).do you get a 2 second run pump prime when the key is turned on and a no start then it could be the crank sensor as the computer looks for a crank signal from the crank sensor when trying to start the car.