redbox33

I own a 04 taco 2.7 and at idle it has a small vibration its been its been like that since i bought it. It has 32k on it. Im just wondering if it has something wrong, ive been in a chevy truck that had 170,000k on it and didnt have as much vibration as my truck, actually, I couldnt even tell it was running, thats sow smooth it was. My idles are normal according to the tachometer in the dash at 850. When Im driving highway speed and come to a stop, my rpms drop like to 800 for 2 seconds then go back up to 850. Im wondering if its all normal? Id like to talk to somebody with the same type of engine and year of mine with more questions like if 2500 rpms are normal for driving 65mph? Any help would be appreciated. Thanks.