To start off, i have the engine code pop up as P1136, and im pretty sure it dealed with too rich-too lean bank. Assuming you have an intake system, could a bad MAF sensor result in the lose of hp??

 

certainly. It's there to monitor air, and set fuel accordingly. If its not doing its job, then your not fueling right, and power will be down.

 

Starting in 2003+ they also added a wideband sensor to the PreCat O2 Sensor which if bad could also make your car run rich/ or lean.

 

A bad MAF will lose HP but replacing it with a new bigger one wont get you more HP. I put a bigger MAF on and it caused some back firing and either a lean or rich code cuz my tune wasnt taking in account for the bigger MAF. I went back to stock and things got better.