Hey All' Ok I have a 2000 Silverado 2500 6.0 Vortec and it just started to stumble you can feel it as it sits there at idle or maybe its a miss and when you give it gas it stumbles for a second then goes away no problems at any speeds so far I just put new plugs in it about a month ago and at the same time had the injectors inspected and cleaned and before that last summer put in a fuel pressure switch. It doesnt feel like a coil pack going bad and its not throwing any codes so I dont know where to look I keep trying to make it throw a code but it wont now it does have alot of miles on it 166719 but like I said no problems until 2 days ago.

I have Mitchells ondemand 5 and thats not helping me at all this version sucks but I have checked my wires and they are all good and coil pack readings are right in range Any help would be great

 

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> I'm definitely no expert on this but I too have had a long standing similar problem in my 1990 C2500 with 257K miles. In fact it has progressed to the point where my truck no longer will start despite throwing a lot of money and parts at it. It was chugging and missing and would sometime die on coming away from a stop light. I too couldn’t get a code but the system in my truck is first generation EFI and is a kludge of major proportion.
First of all from what I have read on this forum and several others these trucks are notorious for fuel pump problems. Suggest you do a “search” for that and check results.
Have you checked your fuel pressure is within factory spec? Have you checked your fuel filter? Mine was plugged. What about plug wires? Are they all free from nicks or abrasion? Sometimes they can vibrate or be affected by heat and produce intermittent shorts.
If it was a coil in most situations if it goes out and stays gone, it won’t be intermittent. In many years with various vehicles that has been my experience.
Don’t know if that is any help or food for thought but from talking via phone to several certified mechanics I'm told there are so many variables involved with these vehicles they all suggest just get it to a knowledgeable shop with a good reputation for solving these mysteries. In the long run I’m finding all of the money and parts I have thrown at my truck, via so called “mobile” mechanics assistance, has proved futile and while I have copies of the factory service manuals I just don’t have the dexterity to crawl over and around the thing probing every little wire or connector.
Best go to the dealer (yeah I know the $$) or a highly recommended neighborhood shop. After 3 months of chasing my problems that is where I am headed ‘cause I’m still parked in the carport and depending on friends or taxi’s for transportation.
Good luck.

 

my friends 2000 does that too and its mostly only when its cold but i think its a small vacuum leak thats purging

 

I had this issue with my truck. It would stumble from a dead stop and that was it. Well the other day while perusing a local junkyard for other misc parts I picked up a newer resonator box (part on top of the Throttle body - says Vortec) I think that's what it's called....and forgot I had broke a piece off way back when. Upon replacement of this piece my truck ran phenomenally better. The stumble stopped. So I would look for a vacuum leak or check, the IAC, or clean the MAf sensor. Good luck and I look forward to reading your fix and solution.