It,s a 89 jeep 4.0 auto and yesterday was raining sleet and about 0. Celsius which is 32 F..I had wipers,heater full blast and headlights and radio on and it would buck on me driving on a level road about 30 mph.Turned everything off and it quit.It has a new battery and I did put bigger grounds on.I don,t know where to start.

possibly coil...?

Please clarify what you mean by "bigger grounds". What does "bigger" mean, how did you do it, and which grounds?

The reason I'm asking for specifics is that these beasties are famous for ground problems, and there are quite a few you need to worry about. I'm guessing you didn't get all of them.

Check Cruiser54's tips for good info on.... well, just about everything for your Jeep, but especially the grounds!