When I put my truck in park it's tack goes up and down could that be from being too lean

 

Mine does this when the heat or the AC is on. When I shut them off it stops.

 

When I just come to a complete stop it does it rarely but mainly when it's in park but I tried that already

 

It sounds like the IAC valve is going bad. I'd check there first. It is searching for an idle point. Rarely the TPS has been the problem but still might be the culprit. Check out the IAC then if its not the problem check out the TPS. Good luck

 

as long as your idle is normal while in park, what you describe is perfectly normal

 

Sometimes it almost stalls out tho