I have a 93 Dakota, 178K 5.2 V8, oil change every 2500 miles since 100K miles, and most of the time I start it up it feels like its missing for anywhere from 5 to 15 minutes on average. It has all new cap, rotor, plugs, plug wires, coil, completely rebuilt computer(if you want to call it that), it was also sent back and re-tested, I did try different injectors a while ago and still did it. Battery is new. I'm looking for ideas on what else to check. I don't believe the miss to be spark. I'm guessing lazy fuel injector if that's a thing. Iv pulled spark plug boots trying to identify which cylinder when the issue is occurring and all cylinders do the same thing. Iv also pulled the connector on the injectors but have not been able to identify which cylinder. When changing the plugs I lined them all up and they all looked the same. I'm hoping I'm not the only one that has ever experience this. When not missing it runs like a sewing machine. I'm stumped.

 

What brand/type of plugs did you install?

 

Autolite 3924

 

I'm no mechanic but kinda in the same boat as you. I have a 1993 FWD Caravan with all new ignition pieces including crank & cam sensors.
Same time I just installed a used engine and the car had a full tank of 2.5 year old fuel .... so naturally am fighting a few bugs.
One bug is the way it runs when cold .... It runs rough, the idle fluctuates, leaving a stop sign on a road with 55 mph speed limit I have noticed it popping back through the TB and the car bucks. ..... Something is seriously not happy. Once it warms up it runs perfect.

Just yesterday I noticed a vacuum line that got knocked loose on the TB, I plugged it back in. This morning when I started it up, it seems to be back to normal now with a steady smooth idle and no fluctuation.



As I said, I'm no mechanic so I'm not sure what that vacuum line operates ... Warmed up the motor runs smooth and could not hear a hiss like a vacuum leak .... there was no reason to suspect a vacuum leak. I have been flushing out the coolant system more days then I care to admit, and working with the hood open and engine running .... no indication of a vacuum leak. .... So I looked around inspecting the vacuum lines and also have another that has come loose. That one I have to raise the car on jack stands and get to it from underneath tomorrow.

So two disconnected vacuum lines and the car runs fine with no indication of vacuum leaks ...... I would not believe it myself except it just happened to me.
Just a suggestion to check your lines, especially on the TB. If you have a loose or leaking line .... it might do what you are talking about.