Steering Wheel Shakes Stops Shakes At High Speed?

I Have a 2004 Honda CRV i bought brand new tires for and they drove perfectly fine and smooth

later that night i got a puncture and a flat tire which i fixed with a plug kit with no leaks

the next day when i sped up to 65 miles an hour the steering wheel will shake a little for half a second then stop for a second then shake again over and over

the faster i go over 65 the shake stop gets faster

and under 65 it drives smooth as glass

Is this a major concern?

Yes. It is.

The plug made it go out of balance. Take it back to the dealer for replacement (if you paid for that).

If you didn't pay for road hazard insurance/replacement then have them remove the plug and patch it. Followed by a new balance.

http://autorepair.about.com/od/fixityourself/u/path_DIYrepairs.htm?ad=semD&an=msn_s&am=phrase&q=car%20maintenance%20and%20repair&dqi=&o=7930&l=sem&qsrc=999&askid=fbde64ce-6e66-4a6d-b376-f7eff5263c27-0-ab_msp

Somethings not right. Either there's a defect in one of the tires, your plug kit caused a problem, or one of the tires was improperly balanced, or the lug nuts are loose. I would go back to the shop you bought them from and have them figure it out.

Plugging the tire may have caused an inability for the tire to be properly balanced, which would indeed cause a shake or vibration. Have the tire center who plugged the tire rebalance it for you. Hopefully that will be sufficient to cure the vibration.