So i have a couple things i need help with... first is the car is runin rich, really rich its getting worse gas miledge then my 02 liberty, i jus bought the car and the guy said that he had changed the o2 sensor within the last year so i dont think it is that, i dont have a lotta extra cash so iam trying to pinpoint the most likely cause. the car has an intake, megan header, and 2 1/2" exhaust to the muffler, no cat. also the heater only blows hot air when iam stoped or driving slowly as soon as i go on the highway theres no hot air, any help is muchly appreciated

 

Sounds like you may be running without a t-stat or one that has stuck wide open. When you start it up, does the lower hose stay cool/cold while the top gets hot? (If not then it is the t-stat.)

 

yep sounds like a thermostat is stuck open. the engine runs too cold (water temp wise), and typically stays in the "warm up" cycle of the fuel maps, which is rich, to help the engine during start up.

 

Is this the same post about this issue, or a repost?