Hey guys when I accelerate and if my rpm goes over about 3500 my RPM would start jumping up and down between 4000 and 6000 until the gears changes. this usually happens when i'm entering the highway. do i have a vacuum leak? and how would i go by fixing this problem. my teg is an automatic. thanks

 

Going on the highway? You sure it's not your car downshifting? Mine use too downshift weird because my fourth gear was dying so it would jump to like 5-6 k because it was downshifting and then go back to its proper rpm range when it engage again. If it is a vacuum leak, simply try searching for it. You might be able to hear it.

 

ignition module is on it's way out.