I can't pass emissions

Hello everyone! I got a huge problem that I cant solve. I got a 2002 745li that can't pass emissions. Check engine light is on for "emissions related fault" code p2177 and p2179. Meaning its running lean on idle for both banks. I've done all parts required but it's still popping up. Once every blue moon it would turn off but would come back on within 25 miles. I get 14mpg combined driving normal. On the highway at 65mph I get 24mph and 55mph 25mpg. I'm really at my wits end and so are the specialist. I know these e66 have a carbon build up issue in the engine, that can be removed with a machine ($$$$) but im not going to to do that. Please help