On a 1998 Chevy Tahoe 350 with a 5.7L Vortec engine, the ignition module isn't a separate, easily identifiable component like in older vehicles. The ignition control module's function is integrated into the
Powertrain Control Module (PCM). The PCM is the main computer for the engine and is usually located under the dashboard, often near the center console or under the carpet on the passenger side.
You won't find a separate "ignition module" to replace. If you're having ignition problems, the PCM itself is the likely suspect (or other related components like crankshaft position sensor, camshaft position sensor, etc.). Diagnosing ignition issues requires a scan tool to check for diagnostic trouble codes (DTCs) stored in the PCM.
