I have a 01 ram 4x4 with a 5.2L, I can't find any info on the correct octane grade for my truck. I'm running 87 octane but it almost sounds like a diesel, not all the time. Does anyone esle have this going on?

 

your owners manual states that for optimum performance and gas milage 87 octane is the best choice... atleast thats what mine says and its an 01 5.9L i didnt believe myself...but for some reason i get better milage with 87 then i to with highgrade like 91 or 93

 

You might have something wrong with your truck if it's soundling like that [>:]

Either that, or your truck has a Mopar Performance PCM or Reprogrammed PCM in it. Those require you to run premium fuel. [>:]

 

Ya, the owner's manual says 87 octane will give you the best performance. BUT, I thinks that kind of hard to believe. For kicks I ran 93 Octane and it did improve my mileage by about 1 1/4 mpg.

 

Any mileage gain you may have seen was NOT becaue of higher octane fuel....unless you have a tuner and were supposed to be running it in the first place.

Otherwise, the change could be due to better quality fuel....no ethanol....or changes in your driving. How many tanks did you run to get that change in mpg? At least 5? Because 5 is the minimum for a good average

The change definitely wasn't because of the octane rating

Higher octane boosting MPG (or power) on a motor not setup for it is a myth...just like TB spacers

 

Burning Rom; I don't know what to tell you[&:] My average for 87 oct was about 12.2 mpg. And that's babying it on the take offs.

I ordered a Superchips tuner which requires the use of 91+ octane gas. Superchips claims the tuner can improve mileage up to 3 or 4 mpg. So before I installed the tuner I check mileage with 93 oct gas, just to see if the extra mpgs actually came from the tuner or the higher octane. I ran a couple tanks through with the 93 oct, just to get a rough idea of the mileage. I didn't change my driving style. I also purchased gas from the same Irvings Truck Stop that I stop at every week. Both tanks clocked in at over 13 mpg. I realize that doesn't creat the most accurate records, but oh well...

At that point I couldn't stand the wait any longer so I opened up the Superchips Tuner. I haven't had it long enough to get a cood idea of my mpgs, but it seems to have improved some more.

Soo... I dunno - go figure. [sm=confused06.gif]

 

Does the regular unleaded fuel at that station have a 10% ethanol blend?

Premium is usually not blended with Ethanol at most stations.

If it does, then there's your answer right there.

 

Not sure. I'll check next time I stop though. [sm=gears.gif]

 

There is nothing wrong with my truck, it runs great. Do you know how to check if the PCM is not stock?

 

Diesel sound could be caused by a leaky exhaust or even low oil levels in the engine.