Well. even Weber/Redline say their carbs sometimes need to be recalibrated to perform really well. Escpecially if your jeep deviates from stock (headers, etc)
Here's a link that mentions a jeep jet kit at the bottom.
Making The Right Choice 32 or 36
It would really help to know WHICH weber carb you have to make any suggestions. There are different types/sizes suited to different engines.
The 32/26 is most popular for stock 4.2 motors. Then there are larger ones that are more suited for hot-rodded mills.
Assuming your ignition timing is okay, and that you have the 32/36 carb...your issues are probably one/or combo of these:
1) Fuel pressure/Float level. Specific to each type carb. IF you idle/accelerate in 1st well....I'd say you're probably ok here.
2) Progressive feature is opening the secondary circuit too soon. You could probably google this info and find it thru Redline (weber carb guys). There are a lot of tuning links on their website.
3) Wrong sized jets for your particular application. I'd do a search for "4.2 weber jets" & see what other guys w/ your combo are running. Where you live (altitude) can play a big part in getting a carb jetted correctly.
The good news is, it's just a tuning problem & won't take much $$$ to correct....you just have to diagnose it correctly.