Strange sounding idle

[GBurton]

Ok Folks
Any ideas on this?

Stock 2001 with about 34k miles. About every 8 seconds I can hear a change in the idle. It sounds like the RPM is changing and I "think" I can see a very slight RPM change on the tach but the blip is so short I am not sure that the tach would have time to respond. I have changed the fuel filter in the past so it should be clean.

George

[pinehill]

George, that may be a sticky common rail fuel pressure regulator (the one on the injection pump). This can be checked with a TechII. You might also try double dosing with a fuel additive containing a lubricant to verify the problem.

[Billy14]

Mine does the same thing but haven't thought twice about it until this topic was posted.

I just thought it was the A/C compressor cycling on & off. I've noticed mine has considerably more injector noise than a friends. Maybe there is a link to what pinehill said.

Think I'll let it idle awhile with the A/C off & see if it still does it. If so, off to the stealer. I've complained to them before about the noise but as usual, they say it's normal.

Billy

[ 07-05-2003, 08:36 AM: Message edited by: Billy14 ]

[raygreg]

I have a 2001 stock with 34000 miles also. At 33000 miles, The injection pump was replaced, and the idle "surge" went away. At 34000 miles the truck quit, and the fuel injection module was replaced. So far it seems to have cured all its problems, idles smooth now. Lost a little confidence in the Duramax, but I think it will slowly return.