need help

[blackcloud]

I just got my 1994 4.0l ohv 2wd 5spd. I have plans for building it into a prerunner and would like to keep the 4.0. I just got it running on 6 cylinders cause the coil pack didnt have spark on cyl 2. From a cold start it runs fine and sounds good after about 1 min of running a faint knocking starts. When revved the knocking sounds a lot louder between 2000-3000rpm and goes away at idle. it will also go away with stedy acceleration on the highway but that is under load. if there is no load on the engine (in neutral) it will knockwith any kind of increase in engine speed. It sounds like it could be a lifter cause a rod would sound worse when cold right? Any help would be great i have read many posts about similar sounds but none with the same symptoms as mine any help would be greatly appreciated.

 

[Duane867]

A rod or rod bearing will act up when the engine is cold due to lack of lubrication some times. So will the valve train too though.
1st thing I would do is change that oil. Who knows how long the coil pack was bad and that thing was running on 4 or 5 cylinders. Gas does not stop being delivered to a cylinder that is not firing. It will flood the cylinder, wash down the walls and go straight through to the crank case thinning the oil some thing fierce. It can cause the problems your having now if its thin enough.
Change the oil 1st then see how it acts.

 

[blackcloud]

I will give it a try and update with the results