2004 acura tl with 197k car has no light on when its scanned doesn't show it misfires but you can feel it or just open door and the way it feel and shakes
i didn't have that before i changed my spark plus to NGK LASER IRIDIUM Spark Plug IZFR6K-11 # 6994.. would they cause that misfire or what is going on because it scans like nothing in wrong in car. when car in park or neutral it shakes hard but once it pass like 10 mph car drives smooth .

what should i do ?

 

If this started immediately after you installed the plugs, you probably either used the wrong plugs (did you install the exact stock spec NGK Iridiums?), or you may have made a mistake in the installation--perhaps one of the coil packs is loose, or there is a missed connection.

This symptom sounds a lot like one cylinder not firing.

 

perhaps the gap on the spark plug is off, maybe it got hit by accident. or plugs not tightened down enough

 

i was also thinking it might be the gapping but it said they already come pregaped .. is it bad for the car ? because it drives fine. should i buy different spark plug? because i took them off and put them back on

 

Two possibilities in my mind for a rough idle/low speed shake with no code:
1) Bad motor mounts
2) EGR valve is dirty/bad-- in this case, a code will ultimately show up.
It looks like you've got the correct spark plugs.
I would have checked the gap before putting each plug in the car, though.

Welcome to AZ.