I have a dodge avenger 2013 and i put the regular gas in it
what would happened
As opposed to what? Premium gas? E85? If you normally run on premium and you accidentally used regular, no big deal. Might take the engine computer a little time to adjust so may lose some gas mileage in the interim. Just run it out then switch back to the premium. I know the factory recommends 89 octane for the 3.5L, so it's not like certain engines that must use premium or risk knocking. If on the other hand you run E85 for their flex fuel engine (3.6L) then you aren't losing anything by running regular. Most people in fact prefer regular over E85 for their flex fuel option vehicles.
I doubt you would notice a difference.
I have a 2012 Dodge Avenger 2.4L It don't won't to pick up speed when I drive it.. Is it cause the regular gas I use.. Or u I need to switch back to Shell B-day Power....