Engine sputtering

Why does my 1998 dodge grand caravan run great sometimes, then backfires, coughs, and spudders other times?

Engine Performance problem
1997 Dodge Caravan 6 cyl Two Wheel Drive Automatic 114k miles

After the engine is warmed up, when at stop, or idle, coughing and sputtering kicks in right away upon accelerating, with a follow up of possible stalling.
If accelerating very lightly from stop up to the 20 - 30 mph range, this is sometimes avoided.
This does not happen when the engine is cold.

Could this be a faulty EGR, air, dirty fuel injector, or fuel /filter problem? A 15% ethanol blend is in the unleaded gas.
Thank you

While driving my '97 Dodge Caravan SE on the highway at various speeds, it will shutter making the whole van shake and the speedometer needle flop around going from 50 or 55 quickly falling to 40 and then back up to original speed of 50 or 55. All of this happens in a matter of seconds. It then resumes normal speed and drives just fine for awhile, and then all of a sudden it will do it again. If cruise control is on when this happens it will shut the cruise control off. Also, it dies when stopped at a red light. It will not stay idleing. Starts right back up no problem.

I have a 97 Caravan 3.8. Lately the car sputters while idling and while driving. Sometimes it even makes a sound like a misfire through the carberator, but it doesnt have one. Anyone have any idea what would cause this?

The codes I got are 12454327272155

Do you think its a bad injector or fuel filter? If its an injector, how do tell which one is bad?

1997 Dodge Caravan SE w/190k+ miles. After successfully replacing alternator(!), Van ran fine next day. After fueling vehicle same day, ran fine for +-10 miles, then an intermittent cut-off/sputter 1-10 seconds long about 5 miles apart. Suspected bad fuel, added injector cleaner. No change. Drove another hour or so, sputter began to worsen. Pulled over. Engine ran fine at idle, but as soon as load put on would start sputtering. Drove a mile or so with engine acting like plugs failing one by one - check engine light comes on, and finally cuts completely off. After +-10 minutes was able to start, but barely running - enough to get off road. Engine turns over but no start.
Luckily there was a auto service center in strip mall where van died. Tech could not put diag machine on, but checked basic electrical and fuel pressure. Tech indicated he thought timing chain "something major broken inside engine" because of "how fast it was turning over".
I'm not an ASE, but I've had timing chains fail before and it's not a gradual thing. Just doesn't ring true to me. As I'd just gotten fuel before problem began I suspected bad fuel or clogged injectors, but engine won't even try to fire - just turns over. With having just replaced alternator, I'm now wondering if ECM is fried?
Thanks for all your help!

I have replaced so much on this van and now it is sputtering and dying. It will idle, but, the RPM jump and then be fine. Then we start driving again and it dies. I replaced the fuel filter and fuel pump. What should I be looking at. When this happens, it does blow white smoke.

There is no mixture. Could it be a throttle or idle sensor?

It does not always blow white smoke.

It only does it when starting it in the morning. But, not at any time after that. It starts fine usually. It starts sputtering and dying about a mile down the road. After that, it is hard to get started. When it is finally started, pressing on the gas, it sputters. Then, when taking your foot of the gas, the RPM gauge shoots up to a range of 5-9 and then dies.