Car question

[tw]

If a fuel filter is clogged, the problem is easily identified so that an intermittent no longer exists. Simply remove the filter and blow through it. Flow would be obvious restricted. Or backwash the filter with a solvent. Either means you know if a problem was or was not solved. Since you have a new filter, then blowing through the old and new filter will make any restriction obvious.

Shotgunning did not find the problem. Leaving you unsure if anything was fixed.

Or the entire fuel system could be tested without replacing or buying anything. Shop manuals may state how many pints a fuel pump will pump in a specific time. Then the pump, intake filter (inside the gas tank), pipe, check valves, and in-line filter are all verified as a complete system. IOW a problem is known solved because the problem was first seen before corrected.

Concept was taught in CSI: "Follow the evidence".