I sometimes get a dominant cylinder... Meaning that when at idle you can hear one cylinder hit harder than the rest... sounds like the injector is firing harder or something. I know these things use a pilot injection before the main injection and it seems to not be getting the pilot one on one cylinder. The tech has not been able to hear it since it is one of those "never does it when you want to" deals But I have called him on my cell phone to let him hear it and they have no idea...... It happens at all tank levels so it's not a fuel temp issue, that was his first idea. Any help would be greatly appreciated.. By the way my mileage is slowly getting worse all the time.. now have 11k on it in 6 weeks!!

 

if its like a lope mine does it sometimes as if injector is carbon over try some diesel injector cleaner. I put my chip up all the way and got on her I guess egt's where up and burned carbon off cause it does not do it no more.
Most say its a bad injector more like dirty injector.

 

I put three tanks of fuel with a healthy dose of lucas injector cleaner in it yesterday and it seems to have gone away for now. I can't see how I get carbon buildup on my injectors. My truck is "used" everyday and most would say pretty hard at that!!! I pull an 8k trailer empty and most times load it to 15-16k all the time. I have to get about half throttle before it even moves! So I will see if it comes back and deal with it then. thanks for your help...also any more ideas would be greatly appreciated.

 

Underwood, I have had a similar noise only on a few occasions when I had to fill up with fuel from questionable stations. It was mostly noticeable when slowing down to a stop and coming to an idle. Typically I only run 50 cetane premium fuel that I have access to, but a few times in a pinch I've had to fill with the regular 40 cetane garbage truck ca-ca #2 ... Ohio is known to be in a PADD (diesel distribution across the country is sectioned into various segments called PADD's) region having some of the worst diesel in the country, which led me to the conclusion that it's possible you're getting bad fuel.

This may be obvious and you may have done it but it may be worth it to rule out dirty fuel and air filters by throwing in fresh ones...considering you said your mileage is slipping etc.

 

I have concidered the filters and will be replacing them on the next oil change at 15k in a few weeks. I will be changing basically everything, fuel,air,trans, and trans fluid,and both diffs. everything will be amsoil accept the oil filters since I get a screamin deal on them at napa (wix). Otherwise the donaldson filters are about the best I have found with amsoil I also have access to hastings filters but have not run across any that fit my applications yet. Thanks and keep them cummin!!

 

Have you considered changing your fuel source?

 

I have gotten fuel at a few other places when out of town but have never paid too much attention to how it worked because I was on the road and not in jobsites much.

 

If you only hear the "one cylinder noise" when you are at idle. and in gear, it is most likely the fuel pump. I thought this was the case with my 05, instruments for measuring this kind of noise indicated it was coming from the fuel pump.

 

Good point there Rod , there has been some issues with the pump making noise and not having any problems.