Help any one else's toddler done/do this?

[user1479941108]

Hi i have a 2 and 1/2 year old ds,
He keeps doing this weird grunting energy outburst.
He can be doing anything from sitting watching the tv, playing with toys etc...
Out of no where he'll go bright red start doing a weird grunting noise and then start having a random energy outburst running around. Yesterday he fell asleep or appeared asleep in the car he was obviously restrained in his car seat, so when he started going red and grunting he flapped his arms about instead as he couldn't run.
This happens everyday at somepoint.
Any one know what this may be?
I've spoken with the doctor and he said possible trapped wind, questioned some sort of seizure but said because he's conscious he doesn't suspect its that.

Is he trying to poo? Does he normally poo ok?

No his bowel movements are normal, and has one everyday, he's not in any pain either, been docs again today he said possibly behaviour a phase he should grow out of but then why does he do it in his sleep 🙈 he's not completely ruled out some sort of weird seizure but said because of his age there's not alot they would do.... so now I'm just left to sit and wonder whats going on.