Sunfire 98 GT 2.4L jerking

Alright, here's the problem
I recently had an accident, guy cuts me at the last minutes, it was on snow, no choice to go straight into his car !

A new problem came up since then !, car started to jerk, as if it was missing gaz, but it's not !, does this rarely, like 2or 3 times in 2 days and always when i'm on 3rd,4th or 5th gear reving at about 1500rpm, car should normally force while it starts to rev up more ! that's when the jerk part comes in, the car forces to go forward and the car will jerk 1 or 2 times in a row then it is okay !

now, fuel filter has been changer, air filter seems to be clean ! only thing remaining, sparks plugs ? (the car now has 160 000km on it) sparks plugs wires which doesn't seem to exist on these motor ?

I removed the head, (thing with 2.4L twin cam written on it !), i see the spark plugs, and a kind of weird thing "T" shaped that goes into the plugs and there seems to an electrical module too ? what's the purpose of that thing ? what if it's defective, could this be what's causing my problem ?

sorry for the essay, just needed to clarify a few things
Thanks :p