you should be getting better gas millage with the cai... my 1st car was a 94 Camry with a 3.0v6 and i got 19-21 before i put on my cai and exhaust... but after i was getting 23-25... cuz if a car breaths better it changes the a/f ratio and uses more air... but if your computer dosnt change or if you 02 censor is staring to go it wouldnt change the a/f ratio and make you get bad gas millage any way...
my car has ram air, stock exhaust (soon to have 2.5" cat back), lowered, 16" rotas, no ac/pwr steering, and when i went through emissions my car passed better than my parents 06 matrix... just barley better but still better... and when i saw 42.5mpg when i did the math i thought that it was wrong... but i checked... i use full synthetic 5w30 in my engine and trany and those 4 prong spark plugs and the upgraded plug wires