rough idle when cold
 

hey guys the gf has a 2005 corolla 4cylinder with 77k miles on it. when she cranks it up it idles fairly bad but when it warms up its fine.. i am in the process of seafoaming it... any ideas?? do they have a MAF sensor too?? the plugs are irridium supposedly so its not those......

wouldn't be the MAF. that would cause it to idle rough regardless of temperature.

Do you have a check engine light? You should if it's any sensor. That being said, it sounds to me like your coolant temperature sensor.

no lights on... coolant temp sensor?? to make it idle rough when its cold????

yeah, when the coolant temp sensor goes out, the ECU goes into failsafe mode, thinking that the engine is at operating temperature already. So it idles and runs like crap when cold. But when it warms up and is actually at operating temperature, then it runs ok.

Usually this trips a check engine light though.

yeah no light just yet... i wonder if i take it to autozone they can hook it up and see if it reads anything... can it still pick up code even if the light isnt on?

yeah, the ECU stores past codes, even ones that have been corrected. Only way to get rid of them is reset the ECU or clear the codes (which most scanners can do).

that is where i would start, because reading the codes is free and gives you a good place to start checking sensors and what not.

ok good deal


where is my post in the 04 tacoma section?? i tihnk it got moved

my truck is doing the same thing. is this a common problem?