76 Jeep CJ5 - stumbles / bogs down

[wi-cj5]

My '76 CJ5 with a 304 is getting the best of me. I had the carb rebuilt by a mechanic
this spring and it ran way better. Last week I was doing about 25 mph, hit a pothole
and the engine seemed to stumble and then had a huge backfire and blew one of the
mufflers wide open. Got a new muffler but still have the stumbling and then backfire
problem. A good example of what happens - driving along at around 30 mph, hit a
pavement pressure ridge, engine bogs/stumbles - push in clutch fast enough and you
can get only a small backfire, rev engine a couple of times to clear things up and clutch
out to keep going, will bog down a bit at first still but then does the same on the next
bump. I can take it back to the mechanic and leave it with him but I'm hoping there
is an easy fix or some testing/troubleshooting I can do first........

[Plow Dak]

Sounds like your losing ignition and filling the exhaust with raw fuel and or the timing is going whacky. If it's only going over bumps i would start with a visual inspection of all ignition components and double check all connections. Check for things that can bounce around over a bump and possibly ground out. Check your cap and rotor etc. for being secure. Don't rush the inspection. Take your time. You can throw a lot of parts at something like this. I had a vehicle with simular problem a long time ago. Turned out it was a ign switch. The guy had about 5000 keys on his ring and over a period of time wore out the inside guts.
I'm sure you will get lots of other input on this one. Just be carefull playing around a running engine... And bring a fire bottle with ya..

[Pickering Snow]

I would suspect it have a dura spark box going south on you over on the left fender apron its a blue grommet box , you should beable to tap test it and duplicate the problem , or a fuse link or wiring issue either way because a bump in the road causes it you should beable to do a wiggle and tap test and fine it easy enough.