Low gas mileage and loss power

[04COBRAinJapan]

Im trying find out why my gas mileage is down, and the car seems to have lost a little bit of its power. (seems like a sluggish response when i get on it)
Ive changed the fuel filter, plugs, cleaned the MAF,then changed the MAF for troubleshooting, and changed all of the O2 sensors (O2 sensors were not new though). No CEL. Im in Japan so i dont have a tune guy, however i Just odered the predator. BTW they have 99 octane availible here. I usually run 1 tank every month (about 60 bucks now that gas prices are down)

Upgrades are BBK CAI, Borla Stinger and Bassani Catted X.
Any ideas?

 

[MustangMikeKy]

Some say the location of the maf will cause some of these issues. . . try rotating it to 12 oclock, 10 oclock, etc. . .

 

[04COBRAinJapan]

how do i do that? Do i need to break the hex screws and rotate the sensor itself?

 

[03DOHC]

"I" would put the stock airbox and filter back on less the snorkel, disconnect the battery for 30 minutes and retest.

 

[04COBRAinJapan]

Ive heard that BBK CAI arent good for our cars because of the bends. Im thinking it can be good with a good tune

 

[03cobra#694]

"I" would put the stock airbox and filter back on less the snorkel, disconnect the battery for 30 minutes and retest.

This is a good suggestion,it`ll reposition the maf to the original location.