Hi--I drive 2 hours up to LA. I get off freeway, it's fine driving in LA, it do not shake when at the lights and stop signs. I park, go to the post office, get in car, turn it on, and it feels like it's gonna go off. The only way to solve it is to drive foward and then go. Rev it up. Shakes a little now at stop lights, etc. Does this sound like warped brake rooters? No shaking in steering wheel, just sometime in front. Shakes more than usual since I go to LA. Could it be spark plug?