1997 Saturn SC2 CAR RPM STARTS AT 1200 WHEN COLD IN IDLE AN

Tiny
SATURNSC2
  • MEMBER
  • 1997 SATURN SC2
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 139,000 MILES
Hi. Good morning
I would like to know what is the reason why my saturn sc2 will feel as if it is accelerated when the engine is cold in the morning and the rpm will start at 1200 at idle, therefore, when I start to drive, the car will accelerate itself from first to second gear. When the engine is warm already, the rpm stays at 750 and the car feels fine.

is is a sensor problem?
thanks for your help
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Thursday, February 25th, 2010 AT 1:24 AM

4 Replies

Tiny
SATURNTECH9
  • EXPERT
I suspect u might have a bad coolant temp sensor causing the engine to run way too rich. It's screwed into the head below where the upper hose goes on it has two wires a yellow one and a black one. Look at the connector see if it is corroded if it is u will have to clean or replace it. Also look at the tip of the sensor that goes into the head if it's cracked it needs to be replaced. It could even be bad if it's not cracked but they crack alot of the time though. If u replace it make sure u get a brass tipped one the plastic tip ones crack. Make sure the engine is cold u will loose coolant. There under 20 and cause all kinds of symptoms. Also do u have any codes?Let me know what u find.U could also have a vaccuum leak or a sticky idle air control valve that needs to be cleaned. Let me know what u find.
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Thursday, February 25th, 2010 AT 11:15 AM
Tiny
SATURNSC2
  • MEMBER
Thanks a lot. It gave me a code, and in fact it did throw the engine coolant sensor code, I checked it and it was a broken cable. I put it together and it stopped to shake and the service engine light came off.
HOWEVER, the symptoms of the rpm over 1200 when cold and going to 750 at idle when warm stay.
The car feels like it is accelerated when engine is cold.

Do you think that I would have to replace the whole cable? Maybe would it be a good idea to clean all the throttle body with TPS and idle control sensor?

Any other idea?

God bless.
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Thursday, February 25th, 2010 AT 12:14 PM
Tiny
SATURNTECH9
  • EXPERT
That's good that u found the broken wire.I would follow the rest of my instructions by checking the connector for corrossion and the sensor itself it's really common for the sensor to fail and the connector to be corroded. Check that out then worry about the iac motor being dirty etc vaccuum leaks. The tps hardly ever goes out. Let me know what u find.
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Thursday, February 25th, 2010 AT 12:33 PM
Tiny
1999SATURNSC2
  • MEMBER
Mine always seems to do this. And I replaced the coolent temp sensor that was cracked. I used a brass tiped one when it was replaced. I've heard it's somthing about the transmission starting in third gear to warm the enging faster. Anybody care to shed some light on this?
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Thursday, August 5th, 2010 AT 8:23 AM

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