intermittent trouble with starting - cranks fine, but won't start

[davidfriend]

hey guys-I just recently acquired a Q45 that was in need of some maintenance, I had new belts installed, new fuel filter, new spark plugs, and had the injectors cleaned. After all this was done, it started having an intermittent problem with starting...maybe once a day it wouldn't start right up, it would crank fine but that would be it. I would stop and wait a minute, and it would start up fine. I've taken the car back to the shop, but of course the problem won't replicate in the shop so its hard for them to diagnose. Has anyone run into something similar, its driving me crazy!!!

[loystock]

Did you use OEM plugs - NGK PFR5G-11? Non OEM plugs can be problematic, especially the ones from Bosch.

Check fuel pressure - 34 PSI with engine running, 43 PSI with engine OFF, ignition ON.