I cant figure out whats causing my 98 TJ, 6cyl, to run so rough when its warming up. If its been sitting for any period of time 30 mins or longer. while its going through its warm-up cycle, it runs horrible. Its stumbles, stutters, pops and rattles, it surges up and down almost like its gonna die out, but it doesnt. It does go away after about 10 min of idling. once it reaches its operating temp, its fine and it runs great. Its not showing any engine codes. I was kinda leaning towards some kinda sensor. I was thinking maybe the O2 sensor thats supposed to be on the Cat. I eliminated the Cat converter, but I did weld a threaded bong into a straight piece of pipe and I threaded the sensor back into that pipe, but Im thinking its not reading that sensor correctly until it gets hot, but thats just a guess.
any help would be greatly appreciated