Hesitation and Poor Power - Distributor Coil Resistance Out of Spec + Junction Box 1 Short

Electricalintermediate✓ OP Confirmed

Problem

Car experienced hesitation under load, poor power delivery, and hard starting. The issue persisted for over a year and a half of diagnosing. RPMs would jump above 1000 on startup then settle, and the engine sounded like it was struggling to breathe.

Hesitation under loadPoor power outputHard starting (takes longer than normal to crank)RPMs jump above 1000 on cold start then settleEngine sounds like it is struggling to breatheIntermittent no-start condition

Root Cause

Two simultaneous failures: the original distributor's internal pickup coil resistance was out of spec (resistance increases with heat due to expansion of epoxy potting vs. metal conductors inside), causing hesitation and poor power. Additionally, Junction Box 1 was shorted/damaged, causing a no-start condition. Both issues occurring at the same time made diagnosis extremely difficult.

Confidence

Moderate confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted March 2025 on SupraForums.com