Intake manifold
 

I was wondering how do I clean intake manifold without removing from engine on 2006 hummer h3 I currently have cylinder #3 misfire and a bad downstream o2 sensor and it stalls at stops already cleaned throttle plate and mass air flow I also replaced spark plug on cylinder 3 because it was carbon fouled

I've zero experience with penray but can say that techron has worked well from my many times of use.

I was just showing Dionta how to do an induction cleaning. I've never used penray either, Seafoam is the most effective that I have used.

https://seafoamsales.com/product/sea...ngine-cleaner/

How exactly do you do the procedure with h3 the video doesn't show how to actually do it on hummer h3. I need someone who has done the procedure on this exact vehicle to guide me. I dont wanna make things worse when it's a simple fix to my stalling problem. I only stall at lights or coming to a stop and she starts right back up just will stall again if I dont hit the gas lol

If you are unable to identify a vacuum line to the intake, you should hire a professional.
I have a setup for my H3 that hangs from the hood, with a valve, (like an iv, that drips) and let it run until the bottle is empty. The hose connects to the vacuum port, & plug the original line to the port, while cleaning and I raise the idle to 1500rpms.