need help, blazer hesitating to accelerate
 

Hey, I'm having some trouble with my 00 Chevy blazer 4x4, it hesitates to accelerate and eventually almost gives up. It has trouble reaching speeds of 30 and even more anything higher. It hasn't been doing this for more then a day. It's always been slow and sluggish but this undriveable. I just cleaned the maf and that seemed to do nothing. I pulled all the codes and only one came up p0174 system to lean bank 2. Anyone else have these problems and no the fix?.