On intake plenum there is a rubber cap that seals a hose connection. Take that off add a piece of rubber hose (3/8" )
Now take a thin straw from a can of WD-40 or similar and fit it into hose end using some tape.
Take a cup and fill it with Sea Foam, clean ATF, aerosol can of combustion chamber cleaner from NAPA or a dealership parts counter, or my favourite, plain water.
Start engine and use the straw to sip water into running engine a little at a time, and the carbon will be blown off by the steam generated shock. Do not feed too much liquid at a time or you may get hydrolock.
That is the reason a thin straw is put there.
Heh, yeah I once sprayed some cleaner into my running engine at a buddy's suggestion. I'm sittin there revving the motor as he's spraying into the intake. It almost dies a couple times, but it keeps going.
Later he said, yeah you don't want to let it die on you, cause you can hydrolock the engine. I was sort of pissed at him for not telling me that... 'course, if I'd been thinking I would've realized that fact right off the bat :hammer:
When I used seafoam though, I actually poured the recommended amount (viz the bottle) into the crank and just let it run for a week and a half
Napa is supposed to have seafoam. Honda and GM make something called "Top Engine Cleaner." I used ATF in the intake, b12 chemtool in the crankcase. Lots of smoke generated... Idle seems smoother - seems to have helped.
Just make sure you change your plugs and oil afterwards.
Seafoam is a great product. Just used 2 bottles in my 93 4cyl. Half a bottle circulated though the intake by sucking it up with the brake booster vacuum hose. Half a bottle in the crankcase, and a whole bottle in the gas tank.
After 700 miles change the oil and enjoy a much more quiet engine with smoother idle.
I have heard plain water is just as good through the intake. But you can hydrolock if you're not careful to use just a little at a time.