Gasoline systems
In-tank pump → filter → rail → injector → cylinder. Returnless designs control pressure at the pump. Verify pressure with a gauge before condemning anything.
Fuel system problems mimic almost everything else. Solid diagnosis starts with measurements, not parts.
Most 'bad fuel pump' diagnoses are actually weak voltage, plugged filter, or a fuel-trim issue upstream.
In-tank pump → filter → rail → injector → cylinder. Returnless designs control pressure at the pump. Verify pressure with a gauge before condemning anything.
Lift pump → filter(s) → high-pressure pump → rail (20K+ psi) → injectors. Contamination is catastrophic — fuel cleanliness is everything.
Gasoline pumps typically 100–150K mi. Premature failure usually from running near empty or contaminated fuel.