Are there DIY instructions for performing this service anywhere?

 

Really no because there is nothing to it?

You just let the engine suck in the cleaner thru the intake system. Remember we can't just dump stuff in the gas tank anymore because it does no good!

There is some variation about running the engine and then letting it sit hot with the cleaner partially used. Then after 20-30 minutes start the car and let it finish sucking the rest of the cleaner into the engine. Multiple treatments may be needed and as posted before depending on the level of carbon build up it may not cut it and then you disassemble the intake and blast the back of the valves.

I am not sure that's your problem and kind of just threw it out because nothing seemed to be coming up in your troubleshooting?

Any chance you have a slim camera? I have seen guys using endoscopes to check internal engine parts. They are beyond cheap on EBay and for $20 you could actually take a look before doing anything?
.
.
.