Blow on the pressureline in both ways to see if it is blocked. Due the small diameter it is normal to have some resistance.
Also check if the pressure line itself is not knacked so it will block the backpressure.

And not sure what your experience is but the pressure line is your fuel pump. taking it away takes away the pump what causes a leaner setting. Because these new engines do come with a rich setting for the 1st start and break in you have to adjust it to a more lean setting during the break in proces