Engine sounds different

[Stroken n Smoken]

Ok maybe I'm a little retarded...but lets not deal with that right now For some reason the last couple days my 7.3 just hasn't sounded the same, it sounds almost muffled instead of the normal rattle rattle rattle. I have noticed at an idle in park it seems like there is a slight fluctuation in rpm, just a little surging, but you have to listen very close to hear it, I haven't notice any difference in mpg, I drive 80 mile round trip to work everyday, and no difference in power, but going down the road it even sounds a little different, like in the summer when it 95 deg. out they run quieter than when its in the 30's like the last couple days. Just wondered if anyone has had this before? Where did my rattle go! Thanks!

[dieselfitter1]

Could be your fuel. Ive seen different fuel types (winter blend/ summer blend) cause these issues. Fill up at a different location on your next tank and see if it changes.

[Stroken n Smoken]

I had wondered about this too, I filled up this weekend at my local truck stop, it's a Cenex, and I noticed this issue this last weekend, but I did alot of running around over the weekend and needed to fill up last night before I left work to go home and I filled up at the Shell truck stop next to my work, so between going home last night and back to work today I have over 80 miles on this tank of fuel, and it still sounds the same, and neither place has posted that they are blending yet so I'm like hmmm maybe not that, I dunno.

[redstroker_2002]

My truck is doing the same thing!! I am begging to think that maybe it is because of the colder weather???idk but the one thing i like about the winter is when my truck idles up and the engine warmer thing when that exhaust shutting valve starts closing and with the straight pipe it sounds like jet engines speeding up its sweet!!!!! i get alot of people thinking my truck is breaking or something and i just tell them its my jet!!! lol but i get some people thinkin its perddy cool... I hope my truck isnt screwed up with the serging at regular idling serging

[Stroken n Smoken]

10-4 Yeah I dunno whats going on because when It started I was just going down the road to work and all a sudden its like my truck got quieter, I was like what the !@%$, but performance hasn't change, I only have 130,000 on it so I dont think its anything major, just odd