How hard is this to DIY, just for future reference anyway.
Very simple. If you look around the forum you should be able to find a few decent write-ups with photos. The various products' makers have how-to descriptions and videos on their websites.
Throttle Body cleaning -- First, be sure to order a new TB gasket, for when you seal everything up again. Basically, disconnect the NEG battery cable, remove the big hose from the TB itself (the one between the airbox and TB), then remove the TB from the engine housing. Using a good TB cleaner, soak the surfaces and then agitate with a brush and keep repeating until completely cleaned, being careful to not get any on the sensor parts. When done, wipe down completely and allow to dry. Using a good MAF Sensor cleaner, spray the MAF Sensor, then allow to fully dry. Reassemble.
GDI Intake Valve cleaning -- I used one of the sprays you can inject into where the big hose attaches from the airbox to the TB. The product by Berryman is easy to use, though I used the STP Pro Series cleaner. The product came with a simple list of steps. Go for a drive or run the engine until it's fully warmed-up. Remove the big tube off the TB, insert the thin tube from the cleaner hose into the gap, then reassemble the tube to the TB, with the chemical's tube aimed into the TB. Start the engine. Start the cleaner can, which will measure the volume of spray into the TB intake. When done, turn off the engine, allow the engine to rest ("heat soak") for an hour or so, then remove the can/tube and reassemble the big TB hose. Go for a drive.*
* The STP product recommends that the drive consist of the following: a 20min drive on the highway, followed by a 5min drive at 5000 rpms, followed by 10mins of driving to cool down. Some products recommend allowing the chemical to sit there for 1hr to soak the crud, though the STP product doesn't recommend this. I'm sure a soak following application would give the chemical a greater chance of digging into any tougher crud.
The only thing to be aware of is that some of the intake valve cleaner products don't have an "automatic metered" setting on the can, so typically you'd need a second person inside the car keeping the throttle speed higher. The Berryman product doesn't say that speed needs to be above idle, while the STP product recommends the throttle speed to be at 3000 rpms.
Pretty much, that's it. It is quite simple. Took me a couple of hours including the drive. A nice easy afternoon project.
