okay so my car was running perfectly when i was driving, then i needed gas so i put unleaded premium, thought it was the same as premium but guess not. next day it start idling almost feels like it wants to turn off, but wont because goes back up in rpm. how can i stop the idle? or what could it be?

 

What gas you put in it is not going to affect the idle.

 

this is not the first time. i started putting premium only and then i put unleaded premium and that's when it did the effect.

 

If you don't want the car to idle just turn it off.

 

For the last forty years all automotive fuel has been unleaded. So where are you getting leaded fuel?

 

to answer, switch the ignition key position to off...

but really, i think your map sensor or maf is on it's way out. try putting on a buddy's maf to see what happens.