Carbon build up

I have a 1996 Toyota corolla 1.6 Engine auto tranny. 153.000 mi well maintained and is in great condition runs good. But most of my driving is in town(I drive 25.000 mi a year) I wonder if I am getting any carbon build up because of in town driving and if so Is there a save additive for carbon build up I can use Thanks ever one.

If the engine runs well then you do not have carbon deposits.

Techron, seafoam, and a long highway drive are the simplest,

What brand of gas do you use?


I have heard good things about Seafoam, and I have used it and not noticed any benefits or downsides, really, aside from maybe wasting $8. It’s safe, though.

That used to happen to cars from the Age of Carburetors, not so much with fuel injection.


Then you didn’t meet one of my former cars. A 1997 Mazda Protege with EFI. It had a severe case of carbon buildup

Well, you’re right in that it isn’t super common

+1 to JT and Keith’s posts.

Carbon buildup comes from incomplete combustion of the gasoline. In a “rich” mix, all the carbon in the hydrocarbon molecules (the gasoline) doesn’t get to marry up with oxygen and create CO2 and CO, and it coats the surfaces in the combustion chambers. Fuel injection system vaporize the gasoline far better than carburators so they need less fuel to get the same amount of energy, and modern metering systems do a far better job of metering the fuel. There remain very few unaccounted for carbon molecules after modern combustion has taken place.

I recommend against additives in well maintained modern engine. Their only real value in a well running modern engine is to help you sleep better. The can, however, do that in some cases.

At 153k miles it’s possible that carbon could be an issue; especially if the engine has been running for ages on old spark plugs and considering the predominantly in-town use. EGR ports can clog and the driver may not even be aware of it.

There’s also the issue of oil consumption, the PCV system, etc which can cause carbon buildup.


I’d avoid gasoline additives unless you have a fuel related drivability problem and a knowledgable mechanic , unbiased, recommended it. You do probably have some gunk building up in the throttle body. I think the best way to address this is to remove the throttle body and have it cleaned up on the bench. I recently did this on my early 90’s Corolla and it wasn’t a very big job. You never know how the engine parts will react to contaminants not designed to be handed by the engine designers, so I’d avoid spraying anything into the throttle body with the engine running, especially if you have a MAF on your engine. When you remove the throttle body for the clean-up, you remove all the cleaning solvents before re-installing, so there is no contamination.

That’s the problem with these cleaners. They take the gunk out, but it goes through all the system contaminating everything. It can even sometimes block a passage. Even a small blockage can be severe. But if you are really having problems, it will not hurt to try.