rich gas code 172 have changed throttle pressure sensor, maf ,spark plugs and wire air filter,front o2 sensor what more can i do. 2008 chevy impala 3.5 l

Hello, vacuum leaks would cause a lean running code, not a rich one. You would be looking for an air restriction - not abundant air. Or, too much fuel being delivered without being commanded, such as a stuck open fuel injector. It's definitely a concern that must be resolved - so it might be that some hands on professional testing is warranted. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops