2000 Saturn SC1 idle

Tiny
JHASSELL
  • MEMBER
  • 2000 SATURN SC1
  • 4 CYL
  • FWD
  • MANUAL
  • 125,005 MILES
When the car is stationary with no road movement the car idles at arround 15 - 1800 rpms. When road movement is presant and the clutch is depressed the rpms will jump to 25 - 3500 rpms and will not return to the fast abnormal idle until the car comes to a complete stop. I have checked the operation of the butterfly in the throttle body and its movement appears correct. I have also checked for vacum leaks maybe the pcv valve has a leak but not the valve the boot that is seated on the valve cover but when I cover with my hand the idle stay the same (no change). About 3 - 4 weeks after problem started sercive engine soon light has come on. Autozone ran the deal and recived a p0301(cylinder #1 missfire detected) code. The problem has been slowly getting worse and soon fear valve and further damage to mechnical parts. Please I am stuck. Maybe a igintion module or or Idle air control or even worse the CCC comuter comand center. Any ideas?
Do you
have the same problem?
Yes
No
Tuesday, January 13th, 2009 AT 7:25 PM

4 Replies

Tiny
RASMATAZ
  • MEMBER
Clean out the idle air control valve and test the throttle position sensor
Was this
answer
helpful?
Yes
No
Wednesday, January 14th, 2009 AT 5:57 AM
Tiny
JHASSELL
  • MEMBER
Yea I have already replaced the IAC valve the Coolant Tempature Sensor and the Throttle Control Sensor. I cleaned the throttle body. Two new codes appeared a p0404 EGR flow ck range and have orderded a EGR valve ans a p0507 idle control system rpm high. I am trying to back off the idle screw and cant. I read in haynes about a IAC plug and removing screw and procedure I am not understanding completely. Should I replace the EGR clear the system and see if the code appers but more importantly the idle is still WAY TOO HIGH.
Was this
answer
helpful?
Yes
No
Thursday, January 15th, 2009 AT 3:47 PM
Tiny
RASMATAZ
  • MEMBER
Too fast an idle speed. If an engine without computerized idle speed control is idling too fast and refuses to come down to a normal idle speed despite your best efforts to back off the carburetor idle speed screw or air bypass adjustment screw (fuel injection), air is getting past the throttle somewhere. Common leak paths include the carburetor and throttle body gaskets, carburetor insulator spacers, intake manifold gaskets, and of course, any of the engine's vacuum fittings, hoses and accessories. It is even possible that leaky O-rings around the fuel injectors are allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft and a defective idle speed speed control motor/valve stuck in the extended (high idle speed) position/throttle position sensor. Also the throttle plate could be binding in its bore and kinked accelerator cable, coolant temperature sensor might not be operating properly misleading the computer that the engine is still cold and computer throwing fuel at it raising the idle speed.
Was this
answer
helpful?
Yes
No
Thursday, January 15th, 2009 AT 3:52 PM
Tiny
JHASSELL
  • MEMBER
2000 Saturn sc1 1.9L SOHC MT

to refresh: I replaced in order
coolant temp sensor
IAC
TPS
I also cleaned the throttle body & gasket

Yes thank you your info got me thinking.
. Its a leak like you say.
So I did so more reserch I have found several cases w/ the same symptoms turns out there problem was a leaky intake gasket.
Then I went out started my car and sprayed carb cleaner at the #1 cylinder intake and a change to the idle occured, so I'm pretty certain thats the issue.

I havent had time to get to this or the EGR valve. I am planing on changing the EGR valve & gasket first and then the intake gasket after that.

I will let you know
Was this
answer
helpful?
Yes
No
Monday, January 19th, 2009 AT 10:59 PM

Please login or register to post a reply.

Recommended Guides