Trying to figure out why my engine shakes when I first start it up but after driving for about 2-3 miles it stops

 

Car info?

Could be an air leak - check fuel trims.

 

Any misfire codes? Even without, worn plugs (on another engine type) did that to me. Warm up resulted in no misfires, but cold start (and engine shudder) was another matter. Replacing the plugs revealed a spark plug gap double of what was spec.