Ya mine does the same upon cold start during the winter months. It goes away after a few seconds. Haven't noticed any issuesVary or elevate. Id think vary and surge are the same. All I know is mine does it when its cold out. Good luck with yours.
What page of the manual? Also, if it means to raise 300rpm like when high idle is on then i understand. But 300+ rpm FLUCTUATION is not normal.in my diesel manual it states that in cold conditions you will experience 300 rpm fluctuation in the engine. Until warm.
I wrote it wrong. I put key in the ignition, turn to KOEO and watch for the glow plug light to go out, THEN i turn the key to start.The wait to start indicator illuminates signaling that the glow plugs are heating up (not ready to start). When it turns off after being illuminated is when the engine is ready to start. A continuous light means a fault with the glow plugs.
Not allowing the glow plugs to heat up can cause the glow plugs to not last as long, sputtering/poor start in cold weather, and flushing the cylinders with unburnt fuel/ increased fuel in oil dilution.
No tune, always oil and filter changes from one of the largest Chevrolet dealerships in the DC area and ONLY that dealer. Its been OKed by GM warranty to replace the DPF exhaust pipe portion but the item is on backorder from GM with no known replacement date. The part at the other dealer is an old stock item.Gm might be a little touchy about replacing a dpf or Scr portion of the exhaust. A non factory tune or incorrect non dexos oil can cause a failure of these parts which they would not cover.
Sounds like you, or dealer has mixed up DEF and DPF. Earlier you stayed you had replaced 3 PM sensors, which is part of the DPF system. Now you say you need a DEF pipe, assuming SCR which is DEF (urea) system . Does anyone at the dealer know how to fix your truck, because they sure are good at throwing parts at it.Now the dealer is telling me that another dealer within a 45min drive has the DEF pipe on a shelf but that GM requires a 24 hour hold to authorize it for warranty repair.
I’ve already lost my ** at the service advisor on GMs absolutely idiotic practices but this takes the cake on the stupidest * **** I’ve ever dealt with on a vehicle.
So instead of sending a parts truck to grab it in the morning and have it done tomorrow afternoon, my dealer now has to wait until Friday to get sent out from the other dealership. It’ll be another 4-5 days before I get the truck back. And that is if GM even authorizes the stupid part exchange.
So it’s a backordered part yet they have them on the shelves of dealers.....idiots.
That would be me. It’s the DPF pipe that needs to be replaced due to a third particulate matter sensor failure and the threads being stripped.Sounds like you, or dealer has mixed up DEF and DPF. Earlier you stayed you had replaced 3 PM sensors, which is part of the DPF system. Now you say you need a DEF pipe, assuming SCR which is DEF (urea) system . Does anyone at the dealer know how to fix your truck, because they sure are good at throwing parts at it.
Not sure what pipe they ate referring to, but if it is an SCR failure, you are among very few. I suspect you need a better diagnostician.