Has anyone ran the combustion system cleaner on a GM 8.1L motor? I can’t find a place to connect the hose?
Any vacuum line that runs directly to the throttle body will suffice. If there is not a traditional or accessible PCV valve, your next best option is typically to use the brake booster vacuum line. If all else fails, you can remove the air intake boot and use a drip method of some sort to feed the cleaner directly into the air stream ahead of the throttle body.