Some Problems

[Knk]

My car is kinda weird. When I first start it in the morning the my digital gauge show the speed is 10 mph when Im not even moving. It dissappear after I drive it. What would be causing that? And my car idles at 1k to 1200 rpm when the engine is completely warmed up and stuff. And when Im driving and I put it in neutral, the rpm stays around 1800 or 2000, it only goes down when I stop and at then its only go to around 1k or 1200 rpm. Shouldn't the rpm go lower than 1.8k when I put my car in neutral? I want to know what would causing this problems and how to fix it at home. And one last thing, everytime I accelerate to around 3k rpm, I can feel a little vibrations from the engine. It happens in every gear. A mechanic say that it might be my clutch or something. Its not the mounts because I just put in new Nismo mounts. Could it be timing chain? I know its a lot of questions but I would appreciate as much help as I can get.

Can someone give me a picture or show me where the idle adjusting screw is on a ka24e.?

[kansas240]

could be many things, vacuum leak, faulty sensor. etc.