well first of my motor in my car burn CRAZY gas...i get about 12 mpg its horrible idk what i could be i replaced map sensor but stilll eats gas like a fat chick at a alll u can eat buffet

then last night i was driving my hatch and then it started to idle at about 2300 outta no where then after awhile droped to about 1300 and started goin from 1600 and droping bak to 1300 like i had a messed up vacum and THEN it was sound FUNNy like it was on 3 cylinders kinda like a boxer motor with exhaust

IDK what to do i kno somone can help....i hope