P0442 Fault Code in 2001 GMC Yukon XL with 5.3L V8: Symptoms and Diagnosis

I own a 2001 GMC Yukon XL equipped with a 5.3L V8 engine. The onboard diagnostic system has returned only one code: P0442. While documentation suggests this code does not typically cause driveability issues, my vehicle exhibits an inconsistent idle—stalling around 500 RPM—and the engine runs roughly. Additionally, the interior lights dim intermittently, and the air conditioning unit stops blowing strongly even at high settings until the engine is revved. I'm seeking advice on possible causes related to the P0442 code or other underlying electrical issues.