I have a friend whose 04 Mazda 6 that will jump once after letting off the gas occasionally. It also stalled one time when stopped to make a turn (started up right away). My first thought was the fuel system may need a little cleaning out because that is what I have done in the past with carb'ed engines. I know this is injected but thought maybe it would be something similar. Any other thoughts?

 

Air filter, nasty injectors, bad plugs, fuel filter, those are things i'd check first.

 

Is it a jump or more of a..jerk? And how did it stall? Was it kind of rough when it cut off?