Kevin,
Could be a few things.... with detail so far?
My first blush is the TEAMRUSH & MSD (Mutli Spark Capacitance Discharge) is the BEST upgrade we can do to a CJ or Jeep from the 70s and 80s..... I did this 5 yrs ago to my
AMC 258 i6 / 4.2l and it screems, breaks both tires loose on gravel just hitting gas in 1st, and I get 23 mpg hwy. When you guys need to do tune ups, use the teamrush parts, spring $
AMC 150 for MSD and leave your stock ignition installed for back up ignition and for when you sell the CJ and keep the MSD for next project.
The MSD & TEAMRUSH is 500% better ignition and you are thowing 500V at the plugs everytime and many times multi sparks per cylinder fires.... I will guess you are a bit lean now. You did not mention what carb you have but lots of posts list the jets they are using. I had to bump up my WEBER jets when I put in the MSD and already had the teamrush parts. Lean condition will make/bog down the engine on secondary, under load type situations. I have also seen lean condition show up going down a steep hill using engine to hold back momentum will get some slight rumble in the exhaust......
I also want you to ck your system and balancer more..... Changed DISTRIBUTOR is what you posted.... so GUESS you took out the prestolite dist/ignition. Did you look at the mechanical/centrifical advance slots by looking down the little holes. YOu want the 13r & 18r slots. Did you find TDC on the compresion stroke for #1 cylinder to install your dist??? What i recommend is lets find TDC, verifty the balancer has not spun, and we have a dist with 13/18r and does not need modification to run properlty. Did you test drill the dist gear to verify it was not one of the hardened gears on the market?? Did you buy a remand Duraspark dist or get one from junk yard, NOS, etc?????
ANS the questions above about dist, advance slots, etc. and will write more what we can do.
Give me some feed back on dist and such before you try to change your jets or mods.