This has started happening in the past couple months. Cold starts are fine.

Sometimes after driving or letting the car run for 15-20 minutes (then shutting it off) i will come back 5 minutes later and the car will just crank and crank. After cranking, if i turn the switch on but not to start and let it sit for a little bit, it will then fire right up. This has happened 3-4 times in the past 2 months (this is my daily driver).

any ideas what may be causing this? fuel pump issue?

 

It's possible that the one way valve on the tip of the fuel pump is failing. I assume you are running a bosch system. You should not necessarily need priming to restart, but when you turn the key do you hear the fuel pump activate for 1-2 seconds?

Next time this happens, have a towel handy to surround the fuel junction at the fuel rail to keep fuel off the exhaust and crack the fuel line open. Hold the solid line with a 14mm? wrench and turn the larger one with a 17mm- just a tad. If fuel does not spray you in the eye, there is a pressure problem.

Although there will likely not be a fire, do this out of doors and have an extinguisher handy.

 

First thing I would check is the fuel pump relay. It is just behind the glove box. Remove the felt cover underneath the glove box and there should be a whitish-gray rectangular box. Next time it won't start, tap it with the plastic end of a screwdriver and then try to start it.

What happens is over time vibration causes the solder joints on the little circuit board in the relay to crack and make intermittent connections. You can take it apart and resolder them.