power problem

Yesterday I took my mac cai intake off and cut it with hacksaw before the mas to rotate my mas toward the fender. I then put on an oil breather cap and finally installed my mils. Put some fuel system cleaner and 93 in the gas tank to burn up some carbon build up. Now the car feels real slow down low! I reset my computer and it just threw another code. People tell me the breather cap will throw a code. Is this true? Why is the car running poorly? Any help would be much appreciated!
 
First thing I would do is get the code scanned.

Did you drive the car for one cycle to let the cpu relearn the fuel mappings. The driving cycle invovles running the car with the A/C on. Read your owners manual to learn about how to properly cycle the car.

The manual also says that running higher octane than 87 can cause a performance decrease.