My car starts perfect when cold, perfect when HOT, (with in short time of shutting off), but is harder to start when warm - like 1/2 hour to an hour after turning off, engine cranks but doesn't catch unless I pump accelerator pedal.

I have replaced all the O rings and did my best to clean the injectors (compressed air, brake cleaner and 12 volts). When reading instructions to remove the fuel rail and did not get gas discharge at the schrader valve I was a bit concerned , but hoping the leak was an O ring. So, still the hard start at warm and little or no pressure at the valve after car sits.

I am assuming one of the injectors is leaking/bad. I am thinking I should get 1 new injector and rotate it though the 6 until my symptoms go away? Is there any other way to check injections without fancy shop equipment?

OR do I look to the fuel pressure regulator? (not even sure where that is)!!

Thanks!

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2004, X5, 3.0, 202k+