did it start this after the new plugs went in, or was it this problem which prompted the new plugs?
does it do this at 2 miles every time you take it out? or is it just after a certain time running?
'93 5.2L V8, Laredo, 242 TC swapped from a 249, 3" Coils up front and Front coils in the Rear, JKS Adjustable Track bar, K&N Cold Air Intake with Amsoil filter, Rear cargo area shelving, and KOR's Steering Gear Brace, IRO's Over-The-Knuckle Steering, Top Light Rail, Top Tire Carrier... for now...
OR If you prefer acronyms: 93 5.2 V8, 249>242, 3" FC, ~2" RC, JKS Adj. TB w/ KOR TB Bracket, K&N CIA w/ Amsoil filter, Shelves, KOR SB, IRO OTK HD steering
Try unplugging the upstream (closest to the engine) 02 sensor . This will cause a engine light but does no damage if just doing the test . Drive it a few days . If the issue goes away , replace the senser with a Mopar unit . I'll describe the symptoms
Happens only within 3-5 minutes of starting , can be cold or warmed up .
Stumbling and backfiring lasts for approx 30-45 seconds , then , just clears up (backfiring most likely a result of trying to accelerate while this occurs)
Once finished it's little hissy fit , it will run all day without issue , provided it's not shut off .
If that's whats happening , skip the test , install sensor