Rough idle and check engine light too!

[Epomethius]

First startup in a bit made for excitement draino. Any recommended mechanics in the Oakland Ca area?

 

[brokedown-SKO]

Your bus should have a typical GM ECU with OBD2. Any autozone can pull the codes from the computer for free, I'd start there.

 

[Booyah45828]

Yeah what he said. If it's got a duramax, you should be able to pull engine codes with any generic obd2 reader.

 

[Epomethius]

Right! P0191

Funky idle went away after warming up. The battery was low when starting and perhaps that was the root cause. The internet has someone with a similar story.

Trying to start the truck with a dead battery will set this dtc also. As will connecting the battery with the key on.

From this site https://www.pirate4x4.com/forum/tow...mp-mode-rough-idle-wont-rev-over-2k-help.html

 

[Rovobay]

I have an LLY duramax in my 2005 Silverado. I use this forum whenever I need to (which thankfully has not been in a very long time) I even got enough courage to change my headgaskets through the info on that site. it took 2 weeks every day after work but several years later. no problems.

https://www.duramaxforum.com/forum/