had my valves adjusted at a honda dealer and at idle my car seems to bit a little shakier than it used to be before the adjustment. the shifter in neutral at idle shakes too to indicate this.

called honda about it, service guy said that its because the engine is breathing better now. that doesnt make sense to me, any thoughts?

 

Assuming that the valve clearance was adjusted correctly, you could try to increase the idle speed by adjusting the screw on the throttle body as detailed in the service manual.

It might also be worthwhile to do a Seafoam treatment on the engine.

Is the CEL ON?

 

One time after I had my valves adjusted, one of my spark plugs was not gapped correctly created a little shake at idle.

 

Adjusting the valves shouldn't change anything except make the engine quieter. Maybe the spark plug wires aren't back on securely? Does it run good on the road but just not idle as smooth?

 

No check engine light and the idle seems steady and normal like before the adjustment.

The mention of the spark plug makes the little vibration seem like a car that needs a tune up but was tuned last year.

 

runs good i guess, hard to tell. but shaking seems more noticable now

 

Do you have a tachometer to monitor engine rpm when idling? If so, what is the warm engine idle speed?

 

on a warmer day its slightly above the little notch above the 0, so maybe 450? colder days it between that line and the 1 so like 650?

 

Your idle speed seems low. For a warm engine, it should be about 700 rpm with no load and should increase to about 800 rpm when the headlights are turned ON.

Try adjusting the idle screw on the throttle body.

 

did you check your IAC valve?

did you make sure your intake valves are properly connected after the adjustment? It could be that the the valves are adjusted too tight if your car is idling too low