Need some help if anyone has had this symptom. 96 JGC 4.0, stock; 42RE just rebuilt. The problem is that after starting cold and running a few miles, the engine shudders violently several times. There will be a few minor shudders mixed in as well. It never shuts completely off, just shudders. This occurs both under hard acceleration and just maintaining speed. New throttle positioning sensor was put in, but still does it. I personally know of 3 other 4.0 96 JGC's that are doing the same thing. I've run through a couple of tanks of gas thinking it was bad gas, but it's still happening. Sounds like a fuel issue to me, but not sure, what with all the electrical issues with this vehicle. Any ideas where to look. BTW, it is constantly throwing P0300 codes. It lists P0301 through P0306 every time and a random misfire code as well. That's the only CEL that comes up. I clear it and it comes back up within 20 miles everytime. Anyone seen this before?
Thanks in advance for any advice.

 

I know some 4.0l zjs had coil problems.......my buddy replaced 4 in his in two years. Then he got one from the dealer and hasnt had the prob since.

 

I agree sounds like a fire prob not a fuel. I just replaced mine and she fires up like a champ. New wires and plugs and coil and it would prob be gone. But if it is fuel maybe new filter, ? Maybe yours is clogged?

 

Thanks for the input guys. I plan on doing a total tune up this weekend. I haven't done one since I bought it. One thing I forgot to mention is that it only does this when I first crank it up. It cranks fine and runs fine for a couple of miles then does it's shudder thing, then runs fine. I drove it home from the transmission shop last Friday and it ran fine, after the initial shuddering, for the remaining 120 miles. With it being intermittent like that, I'm kinda stumped. Appreciate the replies.