Cold Shifting

[bradmax]

My 2004 Chevy Aveo seems like it revs a bit higher when it's cold out. That normal? I had a transmission specialist check it out and he said it's fine but I can't help but notice a difference in the performance when the engine's cold.

[thehunterooo]

so you are having trouble before the car is warmed up? what kind of trouble are you having?

[ontarian_frog]

It's normal. What makes it do that is the IAC or Idle Air Control. Essentially, it's a choke (the reverse of one really) for a fuel injection motor. It lets more air in to raise rpms and warm the engine faster so that it can enter closed loop mode (run at 14.7:1 AFR) and not damage the catalytic converter.

[Z34guy]

My 2004 Chevy Aveo seems like it revs a bit higher when it's cold out. That normal? I had a transmission specialist check it out and he said it's fine but I can't help but notice a difference in the performance when the engine's cold.

It's normal. My Monte Carlo does the same thing. Your gas mileage may take a dip but don't worry. The car's fine. the computer is usually programmed to compensate for the colder outside temperature with more fuel. you'll lose about 3 MPG at worst (from my experience). It's completely normal.