Tachometer Stuck at 3K RPM - Ground Wire Fix

Tachometer would not read past 3,000 RPM despite the engine clearly revving beyond that. Occurred on a 1988 NA 5-speed after an engine swap with a rebuilt non-turbo 7M-GE block.

Bad or corroded ground connection for the tachometer circuit. Initial community suggestions pointed toward a turbo vs NA instrument cluster mismatch (turbo and NA tachs use different signal methods), but the actual cause turned out to be a grounding issue.

Moderate confidence — Original poster confirmed this resolved the issue