is it required to use a higher octane fuel than regular unleaded in the 5.9 L Durango?

 

I don't know about the regular one but you're supposed to in the R/T model.

 

Only the 00 R/T model required premium for a whopping 5 hp gain. After that, 01-03 R/Ts were made to run on 87 or 89 IIRC.

Don

 

They need at least 87 octane. Except the R/T model with the at least 91 octane requirment.

 

My 2000 5.9L R/T says "Premium Only" inside the gas door. I asked the guy I bought it from about it and he says he never put anything but the cheap stuff in. I've done the same and never had an issue since I bought it last fall. I've never even heard a tick. Now, have I given up some power from this? Perhaps. But I'm OK w/ that. So, technically, yes you are supposed to use it. But if you don't nothing bad will happen... At least not from what I've seen.

 

9.9 chances out of 10 its your exhaust manifold blowing - ticking sound is exactely how it sounded when mine went....Chris

 

I have a 2001 R/T with 125,000 miles all run on 87 no problems

 

What????? He said he DOES NOT have a ticking sound.

 

Dude he isn't the only one.

Those labled with "Premium Only" should use it. 91 octane and up.

There could be some other issues going on without the use of it including engine ware or PCM tuning.