Lately, it doesnt start more than it does. It may not start for 7 days, but on that 8th day, it will start up, and possibly on the 9th day as well. Does this sound like it is the fuel pump/relay, or something else?
The most likely problem is a failed camshaft sensor or mass airflow sensor. Test during no start condition. You can backprobe the wires at the camshaft sensor and check for AC voltage while cranking. If no voltage replace.
Here are troubleshooting steps along with location pictures. If you wanted to make it easy on yourself, drive the car to a parts store next time it runs, have them hook it up on a scan tool and give you the trouble code. That will give a more exact direction in where to locate the problem.
1. At the Mass Air Flow (MAF) sensor, verify that the connection is good and the Black/White wire has battery voltage and the Black wire has a good ground.2. Check the signal wire or the White wire, the voltage should be approximately 1.3 to 1.4 volts at idle. Always verify that the White wire is not intermittently grounding out. If the signal voltage goes high or low in relation to the airflow and the harness and connection are good, then suspect a faulty MAF sensor.