Any mechanic with a scope would be able to see a small drip from an injector. To drop the pressure 40PSI to 20PSI it would need to be a massive leak. Think about it this way, your engine running 6000 RPM does not cut the pressure in half. That would mean that any leak would need to be larger then the max fuel the car would use in any situation. If any engine used that much gas at idle. You are talking about a 2.5:1 ratio at idle it would just die. most engine will stall before 8:1 with 10:1 leaving you plugs black