[mecnec1970]

I just bought a 86 Cherokee Chief with the 2.8 V6, automatic trans. The Jeep was knocking due to a cracked flexplate. I replaced the flexplate and the knocking was gone but still has a bad viberation just sitting and running but with giving alittle gas. I thought maybe it has a bad torque converter so I unbolted it and started the engine. The viberation was gone. I bought the new converter and installed. Today was the first time I got it out after replacing flexplate and converter. About 45 mph the viberation came back alittle. After around 30 miles on it, the knocking started again. It's not in rhythm, but in fact when giving gas it stop's but when stopped or slowing down it's there. I found out the person I got it off of had replaced the flexplate as well about 6 months ago and it had the same problem. Does anyone have any idea's ? Well I know now that the engine is not factory. What if the engine is newer and is internal balanced but the factory one is external balanced what can I do ? Thank's for any help provided..Bob