Rough Idle

[tom4trax]

Hey all it's been a while since I have been on the site but I am hoping you can help. My 04 2500HD is running real rough at idler in drive at stop lights. This is my second duramax and the first time for this problem. I got 55K on this one and already replaced the fuel filter at 30K. Any ideas? Plus my fuel mileage has go to the birds....

Thanks
Tom

[CNF]

Interesting. I also have an 04 LLY with even less miles and have the same problem. Otherwise the truck runs great so I haven't bothered to deal with it. I notice the rough idle only occurs after it has been driven a few kilometers (I live in Canada). It doesn't happen when first started and isn't as bad once the engine is up to normal temperature, so not as noticable during warm months. I first noticed this problem when the truck was about 4 months old. Only 10,000 kilometers (6000 miles) since I changed the fuel filter. I have an appointment with the dealer this Thursday. I will keep you posted.

[madmatt]

I got 55K on this one and already replaced the fuel filter at 30K. Any ideas? Already??? let me get this straight you haven't replaced the filter in 25K :eek: ??? GM recommends 15k but I and many others say no more then 10k while some say even less.Get it changed and add some Stanadyne fuel treatment and see what happens. I've worked on many that come in on the hook for plugged filters w/ far less then 25k on them.

[tom4trax]

My dealer told me every 25K....Guess it's time for a new dealer....I got an appt for tomorrow to change it.

[More Power]

You can get a bad tank of fuel at any fuel station. The first step in troubleshooting just about any engine running problem is changing the fuel filter. Having a fuel pressure gauge (http://www.thedieselpage.com/reviews/jkfuelpressure.htm) can be a asset in determining whether fuel filter restriction is contributing to an engine running problem. smile.gif

Jim