3M 'Throttle Plate and Intake Cleaner' and an old tooth brush. No need to remove the TB - this can will spray upside down. You should also remove the IAC and clean the pintle and passage.
Check your local auto parts store or:
http://www.carfood.net/tri-maxx2000/3mthrotbodsp.html
After your intake is cleaned, you may want to use GM 'Top Engine Cleaner' to remove carbon buildup from valves and combustion chambers. The aerosol can may work at the throttle body, but I like to pour the liquid version in through the PCV hose using a small funnel. This provides the same path as the gunk that causes the problem. Be sure to follow the instructions on the can to flood out and stall the engine. This soak period is important for good cleaning action.
3M also manufactures an excellant combo injector and combustion chamber cleaner but you need their special hose kit to use it. I tried using parts of another brand injection cleaning kit with the 3M chemical. It desolved the rubber inside the hose and I had to pull the injectors and send them out for backflush cleaning.
If you can find a shop in your area that has the kit, this service will be well worth the money.
None of these cleaners should harm your new plugs and will actually clean old plugs.
*** THROTTLE BODY, INTAKE, INJECTOR, AND COMBUSTION CHAMBER CLEANING SHOULD BE DONE AT LEAST EVERY 15,000 MI AS A REGULAR MAINTANANCE ITEM FOR ANY TURBO OR SUPERCHARGED ENGINE ***
