Surging at 1500-2000 RPM After Engine Rebuild - Faulty AFM

Fuel Systembeginner✓ OP Confirmed

Problem

After rebuilding the engine (rings and bearings) on a 1991 Supra, the car starts and idles great with no check engine light, but when trying to rev the engine it surges badly above 1500-2000 RPM.

Engine surges badly when revved above 1500-2000 RPMIdle is normal and smoothNo check engine light presentProblem appeared after engine rebuild with new rings and bearings

Root Cause

Faulty Air Flow Meter (AFM). The AFM was not sending correct airflow readings to the ECU, causing the engine to surge when attempting to rev beyond idle range.

Confidence

High confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted October 2020 on SupraForums.com