wierd bucking at 74 mph
 

I had a weird anomaly on my morning commute. I left for work today as i usually do every other morning thats its not below freezing. I hoped in the car waited until it revved down to 1300 or so and shifted a little under 3000 until it warmed up.

I got on the high way and cruised up to my normal speed of 74 mph and stuck it in cruise control in 6th gear. Then to my surprise the car started bucking but not a normal violent bucking as i have seen in piston engines when a tune up is needed or bad gas it was smoother.
It was like i was tapping the brakes to play a joke on a passenger. You know with a little bit of force but not over done maybe also compared to letting the off the gas completely at speeds of over 100 (not that i have done that is this car). It was maybe a second of 'braking' then a second off.
This continued maybe 2 or 3 times before i took it out of cruise and slowed down. I switched gears changed lanes and let the person behind me pass and then tried to recreate the problem and i couldn't do it.

There were no check engine lights, no stability problems and I was not progressively slowing down. The speedo was still at 74mph until i took it out of cruise. The radio was on and i was in 6th gear so i couldn't really hear the engine clearly. But that also means that it was not making any exceptionally weird/loud noises.

At that speed it is around 3800 RPMS could this be related to the second intake valve being stuck or maybe getting confused, as it opens right around that RPM. I thought this would throw a check engine code though.

Also I am at 3200 miles after my last oil change, I will be doing that tomorrow but it has plenty of oil i checked last night when i filled up with gas.

Any insight would be appreciated I would love to not have to worry that my baby is catching a cold.