2008 mercury opti max

[hgvoce]

If the motor sits unused from weekend to weekend upon initial cranking of the engine it runs but not at full power, seems bogged down. After a few minutes the motor will start making weird noises, almost like a knocking sound for a few seconds then the power increase is VERY noticeable and from then on that day it runs fine. Scan shows nothing ????

 

[schematic]

have you checked fuel pressure and air pressure under these conditions?

 

[Faztbullet]

Sounds like air compressor fixing to go south....