I've got a 2000 with a 4.7L that has a really bad misfire. It started when my wife put in regular 87 octane gas in it. The truck runs best on 92 or better but we can get away with 89 octane. I thought it was because of the low octane gas but after filling up again with 93 it got worse. The spark plugs have less than 3000 miles on them so i really dont know what else it could be. Anyone have any ideas?

 

What kind of spark plugs...

 

not sure we got the Durango about a month ago and and we were told the plugs were new. The more we drive the worse it gets

 

I was also told that my vehicle had new plugs put in it when I bought it but guess what, they were the original plugs. I would change out the plugs, get the copper champions for it, and add a can of seafoam to the tank. See how that would work for you, it is the cheaper way to go to see if it will clear up your problem. You also might have gotten a bad batch of gas before and it would take a while for it to get out of your tank even after a few fill ups. Water has a tendency to do that. Your Durango should run just fine on the 87 octane. Putting anything higher is a waste of money unless your vehicle was used with a tuner with the performance put into the pcm.

 

ever try acdelco platinum plugs? i can get them from work for next to nothing

 

DO NOT USE PLATINUM PLUGS IN A DODGE ENGINE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

these trucks run GREAT on copper core plugs (champions preferably, but autolites are an acceptable substitute if necessary), gap them properly .040, and platinum plugs have been known to cause these trucks to misfire (my old dakota had new platinums in it when we got it and started missing, the solution was to replace the plugs with copper core plugs)

 

+4

Go get some "cheapo $2" Champion Copper Plugs and gap .040 and install.

 

hey yall i put some of them new fangled copper jobbers in it and she runs better than a greased owl. I pulled the first plug and it was a champion copper pulled the next 7 and they were all delco platinums.
Thanks all from the advice

 

Glad we helped you. Like I said earlier in my post, never trust another person in what they said they did unless there is a receipt with the parts on it, but even then I would still be questioning the work.