2009 Chevrolet Colorado P0455, P0442, P0108, P0106, P0107: EVAP and MAP Sensor Issues - Diagnosis & Fixes

I've tried every possible fix on my 2009 Chevrolet Colorado, including replacing the exhaust manifold—yet the issue persists. The vehicle consistently shows diagnostic trouble codes (DTCs) P0455 and P0442 during OBD2 scans. These codes appear intermittently; sometimes one shows up while the other doesn't. Additionally, I'm experiencing multiple MAP sensor-related errors: P0108, P0106, and P0107. I've installed two or three different MAP sensors, performed voltage checks on all connections (which show normal readings), and replaced both the purge valve and the purge vent solenoid in the charcoal canister. I’ve thoroughly inspected all vacuum lines and used carburetor cleaner to test for leaks—no source has been found. A vacuum gauge reading shows a consistent 20:1 ratio under steady driving, which drops to zero when accelerating and jumps back to around 25 before returning to 20. However, the vehicle begins running rough unexpectedly. The vacuum stays within the green zone until it develops a severe loping condition—then briefly dips out of range before recovering. When I drive on the road and the engine starts running poorly, stomping the accelerator temporarily stabilizes it, but the roughness returns shortly after. I'm seeking advice on how to resolve these persistent codes and improve engine performance. Any insights into potential root causes or recommended diagnostics would be greatly appreciated.