Why does my 1996 Toyota 4Runner 3.4 runs good in the winter but bad in the summer
Why does my 4Runner ,run good in the winter and bad in the summer
I have theories on this, as my boyfrind's '05 GMC has a similar issue. My theory: regular maintenance such as changing the trans fluid& filter as well as viscosity of trans fluid &/or gear oil. Higher mileage vehicles become senile.