I have an 08 G37s with 150,000 kms. I have been having this intermittent hard start/no start issue for over a year now and it keeps getting worse. I have replaced the battery, cleaned the MAF's and throttle bodies and I am still having this issue.

The engine cranks fine so I ruled out the battery/starter (correct me if im wrong). Some days it takes 4+ attempts before the engine actually ignites. This only seems to happen when the car has been sitting long enough to cool down. Once the vehicle is running, it is fine the rest of the day and the g runs flawlessly....
This does not happen everyday and I would hate to bring it to the stealership since its such an intermittent issue

Any thoughts????

 

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Test your fuel pump pressure

Telcoman

 

i agree with telcoman's suggestion. check fuel pressure. you may have a bad fuel pump or the fuel pressure regulator may be leaking down to fast and not holding pressure when vehicle is shut off