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Hello!

I have a Impreza 2000 AT. When car is cold when I'm not driving the engine works properly. When I start driving in "Drive"  mode till I touch brakes the engine turning off. It's like the automatic transmittion don't allow to switch gear. I changed sparkling plugs, MAF, iddle ect., nothing helps. 

When engine warms up, everything works perfectly - engine, automatic transmittion...

 

May be someone had similar problem and have any suggestion whet to do?!

 

 

 

Yours sincerely -

 

Edvib

 

 

 

P.S. Sorry for my English! :)

 

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how did you change the idle? IACV solenoid is set at factory and should not be altered.

 

or, did you replace the IACV ?

 

when the brake pedal is depressed , 2 'basic' things happen; there is a demand for 'vacuum' by the booster, and, there is a demand for electricity by brake lights.

 

if the car were idling and you turn on the bright headlights...any problem? If the car is in N , any change in behavior?

 

is the check engine light on?

 

any repairs or maintenance done to the car immediately before this began?

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 I replaced IACV but it didn't help! When car is idling there are no problems! Only problems happening when I'm driving with cold car! The check engine light is off! No repairs or maintenance done before this begam! It seems to me it started gradually! It seems to me that there may be some problems with automatic transmittion. Today when engine stopped Power light on pannel blinked. Heard something about transmittion control unit...

Thanks!

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any more difficult to start when cold than warm? 

 

there is an engine temp sensor (not the same as the coolant temp gauge in the instrument cluster) that the ECU uses to determine when it should 'choke' the car. (send xtra fuel due to low temperature) 

 

I suppose it's also possible something elese is changing with temperature; a vacuum hose leak or ????

 

any smell of fuel when cold?

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I'm Confused... (normal state for me )  You should have to put your foot on the brake pedal to shift from park to drive ???  I drive stick shifts , but most all auto trans will not come out of park without your foot on the brake....  you mentioned that the "power"light flashed ???  Did you mean the auto trans light ? Europe market cars may have differences from the american market.We do not have a power light.  As Lucky Tex asked, have you tried cold starting the engine in neutral , then shifting to drive ? As stated the coolant temp sensor could be malfunctioning, not telling the ecu the engine is cold.   

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The problem started when outside temperature is about 0 degrees Celsius or below ... There is no problem to start the engine. But after I start driving when I have to slow down (near crossroad) engine stops. After about 10 minutes driving everything is normal. Thank you for your advise about engine temp sensor. It may be the reason of my problem. I' ll look for replacement and then check. About "Power"  light - on gear box switch I have a button for fast acceleration. When I push the button the green "Power" light on panel is on. Found some information if Power light is blinking may be some problems with Transmittion control unit (TCU). I don' t understand much about automatic transmittion but us I understood there are TCU and several solenoids... May be in cold weather until it warms up something malfunctioning...

 

But anyway thank you for your advice about engine temp sensor!

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how old is the trans fluid? It's also the only fluid you must check when idling. make sure it isn't low on fluid.

 

many people have improved old trans performance with 3 drain and fill cycles of new fluid (this get you about 80% new fluid as only around 1/2 the volume can be drained) . Some have gotten better performance with the addition of an additive like Trans-X on the final fill. Helps to freshen seals and cleam gummy deposits that might interfere with valve function.

 

also, old plug wires can sometimes be cracked and will cause misfires on cool/moist mornings until engine heat dries the water.

 

You MAY have 2 problems but, as you say, it could be all transmission-related.

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Thank you! I changed trans fluid some time ago, but didn' t check the level for some time. Also I replaced sparking plungs and plug wires... It must be some transmission sensor or TCU, or as you mentioned above engine temp sensor. If I' ll solve the problem I'll post! :)

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you might try cleaning it if there is a lot of metallic debris on them, they can be intermittent - but, it is quite old now, replacement is good idea.

 

same for knock sensor, they crack and can cause loss of power. here, it seems inexpensive knock sensors from ebay work well for many people.

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