Fuel Cut at Full Throttle - Failed Wastegate Actuator

Turbointermediate✓ OP Confirmed

Problem

Car hits a wall at full throttle when the boost gauge reaches 8psi. The check engine light comes on for two seconds then disappears. Only occurs at full throttle. Stock boost gauge is pegging when stock setup should only see 4-5psi.

Engine feels like it hits a wall at full throttle around 8psi boostCheck engine light illuminates briefly (2 seconds) then disappearsStock boost gauge reading much higher than normal 4-5psiTurbo flutter / compressor surge present

Root Cause

The wastegate actuator had failed and was seized, not beginning to open until approximately 9-10psi instead of the normal 2-3psi. This caused boost to climb well above the stock 4-5psi target, triggering Toyota's factory fuel cut safety mechanism at around 8psi on the stock gauge.

Confidence

High confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted January 2023 on SupraForums.com