I have codes 171,174 ive changed both o2 sens,maf,pcv and hose,checked for leaks

Ya but were? Any ideas or were to look?

Most effective way to find a leak is by smoke testing!

Checked for leaks with smoke and nothing. It just passed smog and the same two codes came back again? It runs good, but when it gets warm and your on the hwy and put the peddle to the floor it bogs down no power its just flat.