Brand new to forum but I’ve referenced posts here for quite some time. I finally joined. Ive got a 2003 H2 with 100k miles with a whipple supercharger. Truck is idling extremely rough and I’m at a complete loss. I have been working on my own vehicles for many years and consider myself very mechanically inclined but this is kicking my ***.
Here is info so far;

PO300 code
The below items all New ACDelco parts

-Spark plugs (gapped properly)
-Spark plug wires
-Coils
-Fuel injectors (all tested prior to install)
-MAF
-Fuel regulator
​​​​​​-Fuel filter
-O2 sensors with new exhaust from manifold back to include cats.

I’m thinking vacuum leak? I’ve sprayed carb cleaner around all areas I can think of but now I’m thinking smoke test.

Any thoughts out there before I drive this into the ocean?

 

check your fuel trims to see if it is running rich or lean. might want to also check the purge valve.

 

I'll second what bronxtech said, along with the idle timing, throttle position at idle and mass air flow in grams

Neal

 

Thank you. I will give it a shot.

 

Canister purge valve or purge selonoid on engine or just do both?

 

maybe try disconnecting it at the engine port and capping it to see if it is the issue before throwing new parts at it. if the old one is stuck open then it could be the idle issue but if it is closed or capped off for testing and the idle is still bad then it is not your issue. and you need to look further. check the fuel trims to see if it is a fuel delivery issue. worn pump.

 

Purge valve selonoid! Running like a champ. Thanks for your help. I’m glad I finally joined this forum.

 

glad it resolved your issue.