sea foam beats everything possible , once you use it you'll wonder why you never did it before. Once you start you can't stop getting new horsepower. I use it in my 3 cars , my wife's ,my lawnmower and snow blowers.
Does not matter what gas you use the intake manifold will always have carbon build up robbing you of power and fuel economy including the engine being smoother.
I have used the bg stuff (still have 3 out of 5 cans i bought) and it does nothing compared to sea foam , it does very light cleaning but so does throttle body cleaner. I have also used the Lucas stuff and it was no major change.
Try it ,you won't go back
Don't get me wrong they may clean but it is the difference of cleaning power of Camry and a LS both have the same principals but one is much more refined in multiple areas.
It is available at any napa for about $5 and it worth its weight in platinum never mind gold.
On my 98 i drilled a small hole in my plastic intake between the air filter and the throttle body. I then have a small copper valve i use to allow it to be sucked in when i do use it. Some people use the brake booster but i find it too far back and it does not clean the throttle body of the front of the manifold. If you do use a vac line find one closest to the front of the engine.
I do a treatment at every oil change which is twice a year ,May and November.
An easier way is to use 1/3 - 1/2 (my preferred for a V8) a can of seafoam.
let the engine warm up for 2 minutes from it being cold.Seafoam has a low boiling point so too much heat will cause it to evaporate rendering it less effective.
Then let the seafoam sucked in the intake and once it is in shut the car off if it has not already died.
Let it sit for 15 minutes to soak into any carbon deposits.
Restart the engine and watch the smoke screen . it will blow thick clouds of white smoke out the exhaust as the deposits get heated and burnt. Some say it may foul the plugs but i never have seen that on my cars.
The more smoke the more carbon deposits.
It also does wonders in the oil which is partly why i do it at an oil change but it is needed 1 time a year instead. The rest of the can i used for the intake i stick in 1/2 a tank of gas and away i go.
I prefer to do it late at night when no one will call the fire dept as it is quite thick the first time especially.
The chemicals in the cleaners are much too harsh to be adding every few weeks as it can cause rubber seals to expand. If you are having that much carbon build up you have a problem that needs to be fixed . It is like using soap to fix a wound.
when i worked at a german car dealer i learned that vw/audi's product is really Techron by Chevron. The mechanics swore by that stuff. Meanwhile, on the Mercedes side, they used to sell the BG products and the techs there said they were great as well. I've always used techron and that stuff will make a noticeable difference as soon as you put it in, particularly if you put it in an empty tank, then add only like 5 gallons and take a long ride. i've had camry's that wouldn't run come back to life with it.
that's a good gen. maintenance add. the SEAFOAM that everyone is talking about is a great product when you have a problem. we recommend that in my motorcycle forum for bikes that have been sitting a while and the carbs gum up. dump that in the intake running it wide open so it won't stall until the bottle is empty. like a new machine.