Engine Dies Under Acceleration - Hidden Fuel Return Line Leak

Fuel Systemintermediate✓ OP Confirmed

Problem

Car would die when accelerating under load despite having adequate fuel pressure at idle and a functioning fuel pump

Engine dies under acceleration/loadRuns fine at idleFuel pressure reads normal at idleFuel pressure drops immediately when key is turned offSound of fuel spraying audible with engine off and key on

Root Cause

A cracked/busted rubber fuel line section on the fuel return line, located under the intake manifold. The leak sprayed fuel against the side of the engine block rather than dripping down, making it nearly invisible during visual inspection. At idle, fuel pressure was sufficient despite the leak, but under load the engine could not maintain adequate fuel delivery.

Confidence

Moderate confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted March 2025 on SupraForums.com