I have a 4wd 84 Dodge D150 pickup with a 318. I have no problems at all when I'm in 2wd, but as soon as I lock the hubs in and put it in 4wd (4H & 4L) it stumbles and falls on its face like I have a massive vacuum leak. The front end is not a solid axle but I'm not sure where the vacuum lines are and I'm also not sure if there is an internal vacuum leak in the front end. I have had 2 carbs on it. 1st I had a 600 holley which I had no problems with the 1st time. I tried a 600 edelbrock, where I also had no 4wd problems, then I switched back to the 600 holley.. So I almost feel like I might have screwed up a vacuum line somewhere but why wouldn't this be happening in 2wd? Can someone help point me in the right direction.

 

As stated in the thread right above yours, nothing gets posted here. Please find the appropriate technical section for the year of your vehicle and post your question there.