Quick Tip for rough running engine with NO check engine light

Symptoms:

Very common on fuel injected engines that have a rough running engine but dissapears when rev up. When scanned for codes, none is found. This is prevalent especially if your engine has over 100 k miles.

Theory:

Over times, the top end of your engine accumulates carbon deposits on the following parts: cylinder valves, top of pistons and combustion chambers. This affects the combustion efficiency of the engine so that when on idle, the cylinder will fail to burn fuel completely resulting in uneven rpm. Solution? you can use a chemical additive fed in the intake chamber to dissolve the carbon and brings back better combustion and fuel economy.

Repair Technique:

A combustion chemical additive can be bought from any local store together with a vacuum fitting (see picture) so it can be fed to the engine intake at idle rpm. It will come with instruction so you can do it properly. And if you add a chemical additive for injector cleaning to your fuel tank plus a chemical spray cleaner on your throttle body then your chemical tune up is complete! (again read the chemical instruction so you can use the proper dosage and always make sure they are oxygen sensor compatible because if you are not careful, these chemicals can damage your oxygen sensor).