1986 Toyota 4runnerMarch 26, 2015March 27, 2015what would cause smoke from the transmission area when using back pressure to slow down Share Tweet Pinterest Keywords:4Runnersmoke 3 thoughts on “1986 Toyota 4runner” Freeautomechanic March 27, 2015 at 9:30 am Exhaust leak. JonnyandChristy Riggs March 30, 2015 at 10:50 pm Exhaust leak that only happens when I’m using the back preasure in the transmission to slow down really try again Freeautomechanic March 31, 2015 at 10:43 am When your using the engine to slow down the engine is still drawing in fuel for the carburetor, this does not happen with fuel injection systems(when working properly) but does on all carburetor engines. This extra fuel that is drawn in does not burn as efficient and cause excessive smoke and would be more prominent at an area in the exhaust that is leaking. Smoke can only come out of the exhaust if there is a leak.(hole in the pipe) Comments are closed.