This has been a long time coming. For the past 2 years I've been trying to figure out the loss of MPGs and random hard starting (thought it was my fuel pump going slowly). After watching a video on youtube I suspected my throttlebody. Apparently carbon build up in normal on these 3.8L throttlebodies (I know quite a bit about these things but didn't know that!) Anyway, holy hell was mine bad!!!
I removed it and cleaned it up really well. Took before pics of both sides (note how black the inner side was!!) Anyway, on my drive to work today, back to 30-31mpg on the highway. Throttle response is WAY better, and the hard starting is gone.
I'm sure there's a thread on this but wanted to share my experience.
I also removed my 2004 silverado's throttle body and cleaned that (wasn't nearly as bad carbon wise). I will be checking my wife's 06 base grand prix tonight.
Last pic is of the supercharger body. I just bought new fluid to once again swap for the super charger... only way to clean this passage is to remove the upper supercharger I'm assuming? If I'm going that far and have to already remove the fuel rails, I might as well remove the upper intake, thermostat, heater helper hoses and replace them (with the aluminum ones), replace the belt and coolant hoses. And do a coolant swap.
