food nd cars

last night i took off my lid and forgot to put back the sensor. this morning on my way to school i pluged it back in. then at idle all of the sudden my oil gauge is going way low then struggling to get back up... the idling is pretty rough too, almost like its about to die,and when i let off the gas at a speed above 30 mph it almost doesnt slow down at all untill i press the brakes.like the im still on the throttle.. the recent things i have done. ( change oil 5W-30, Turbo108 octane booster, recharged my K&N ) and i just got it serviced less than 400 miles ago. they said everything was fine, LIARS!!! help me out PLEASE!!!

food nd cars

im a newbie.. anyone?