When im sitting in park, the engine like to idle around 6 or 700rpm. It shakes a little bit but too bad but when I put it gear it drops to about 5 or 600 rpms. The shaking is not too bad but is kinda annoying considering all the work ive done to the car since I bought it. I was wondering if I should adjust the idle a little higher. Ive already replaced the plugs ( gaped at .54), wires, distibuter cap and rotor. Ive also replaced the air filter, oil and filter, pcv vavle, and ect.. What else should i check or replace? Thanks.