Would a broken thermostat cause bad fuel milage? my temp would stay at around 140. I just replaced it and im curious if thats the reason my gas milage was soooo horrible.
My engine lights on. What are the other major symptoms for giving bad milage?
plugged exhaust, in dire need of a tune up, cap, rotor, oil/filter, plugs, wires,ect... Vacuum leak could be one, and yes a bad thermostat would not allow engine to run a normal operating temp... possiblities are endless pull the codes find out for sure