96-up uses 2 O2 sensors one pre and post cat. 95-down uses 1 pre cat, so it will never know if the cat is gone. So you will never get a light and no problems at all. Trust me I know. LOL!

 

mynes the 96 and has both o2's it should set a light and wathing the datastream the o2's mimic one another so i should have a p0420 cat efficiency below threshold. it sees the data but doesn't recognize it as it should.

 

i had the same issue ive seen alot of people have had with the dakotas losing power backfireing acting like the timing was off i also changed the o2 egr plugs wires iac and the list goes on just couldnt figure this out it was really eating me up but then i took a can of carb and choke cleaner sprayed around the intake after i fianlly got it to idle and it killed the motor problem all along was a leaking intake gasket the kit is $26 give or take for your area changed the gaskets and it runs like it did the day i bought it plenty of power no smoke no miss so you give it try if it doesnt work your out the cost of a can of spray

 

the problem i found with mine was the intake was leaking i changed the gaskets runs great try a lil carb and choke cleaner around the intake while its running if anything changes or it dies that may be you issue. no more smoke or backfire

 

I have a 92 D150 with a 318 that does the same thing. Idles rough, lack of power, occasional backfire. At 50mph with light, steady throttle...truck shakes violently once it shifts into overdrive. Used to clear up after hitting a good pothole. Replaced plugs, wires, cap & rotor, IAC, EGR, removed and thoroughly cleaned throttle body and still have the same problem. I tried to lightly tap on anything and everything under the hood while it was running to see if anything helped smooth out the idle.(tried to simulate pothole jolt) Crazy thing was...when i tapped the plug wires at the distributor....i got a good shock. Cap is new and not cracked and wires are also new. I would greatly appreciate any suggestions. Thanx.

 

I had the same issues for years with my Dakota and a shop tech finally pulled up a list of Dodge repair notices and it turned out that a large number of Dakota came out of the factory with distributors installed 180 degrees off. (They have a slot instead of a gear). Try rotating your distributor 180°. Mine ran like a beast afterward