Ha-ha - in retrospect: funny leaving the cap on, then having your helper remove it! :/

So, how does one go about checking fuel pressure?

Smoke above 3k: I recall my father purchasing a brand new F-250 diesel in 83. It had a hit and miss bad smoking problem on the highway. We finally realized it only smoked when using the rear fuel tank, and further inspection found a factory-smashed line along the frame.

Starved that IH engine, and she'd smoke like heck.