It just started yesterday after I started my truck up after work. I noticed when I started it up and left it in park it seemed to missfire or something like that. It runs fine then randomly makes a faint chug sound. Then when I went to drive it, it accelerates normal then randomly hesitates for a split second and goes right back to normal. It seems to stop doing it while driving when the truck warms to normal operating temperature but still does it while idling.

The sound and the way it feels makes me think it has a bad plug or injector but I've never had this problem with a vehicle so I don't really know.

Anyone have any ideas?
The truck does need 2 o2 sensors, could that cause it?
It never did this before and it's needed them since I bought the truck about a month or so ago.

 

Check vacuum lines.