Not BG, but I have used this device at a local shop.

http://www.motorvac.com/
I can say for certain that it cleans the engine, plugs, and injectors
very well.  I have it done about once every five years, cost is about
$100, a bit less if you know the mechanic.

I'd say that a good fuel system cleaner (chevron techron, pyrol, or seafoam)
would work well.  Others swear by dribbling a thin stream of water or ATF
fluid into the throttle body.

Frankly, with modern detergent gas the most you need to do is clean the
throttle body, idle air passage, and butterfly with some TB cleaner.
Especially if you have any rough idle.

I had 'just' an induction system clean done once when my Cherokee filled
the air intake with oil spits from The blocked CCV defect when it failed
emissions due to high HC's.  Mostly because it was winter and I didn't
want to take it all apart and clean it myself.

It then passed.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08.  Some Canadian Bush Trip and Build
Photos: http://mikeromainjeeptrips.shutterfly.com