1999 Saturn SL1 Engine idle speed -

ANOTARI

MEMBER
1999 SATURN SL1
4 CYL
FWD
MANUAL
196,000 MILES

I have had this problem for the past several months - when I start the engine it accelerates to around 2000 RPM and hangs there for minutes - it does not drop to the normal idle speed of 7 - 800 RPM. Once the engine warms up it behaves a little better, but not right.

I have a 5 speed manual transmission and when driving and come to a stop and push in the clutch the engine accelerates to 1,500 - 3000 RPM and slowly drops to 700 - but this takes a minute or two.

I can drive along town streets at 30 MPH with my foot off of the gas. - Even then when I push in on the clutch the engine accelerates to 1500 RPM. Only when I come to a stop at an intersection - no forward movement.

Example: driving along at 50 MPH (2200 RPM) and push in clutch ( foot off accelerator) - RPM goes up to 3000 and slowly drops.

I replaced the throttle body and the spring is very strong - but I still have the same problem

3 Replies

SATURNTECH9

MECHANIC
30,869 POSTS

When you replaced the throttle body did it come with a idle air control valve?Also have the car scanned for code's if ut has any let me know what number's they are. Also check the hose that goes from the intake to the pcv. If the hose is colasped or has any hole's in it replace it. Let me know what you find.

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Sunday, June 6th, 2010 AT 5:38 PM

ANOTARI

MEMBER
3 POSTS

I don't know is an idle control valve was replaced with the throttle body - done by someone else with a good used part.

Will check the hose to PVC valve.

SERVICE ENGINE lite has NOT come on - this problem has not triggered a code.

I note that there are two electronic devices on top of the throttle body housing - one on the left end and one on the intake end - probably part of the emission control system - do you think that one of these may be subject to being the source of the problem?

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Sunday, June 6th, 2010 AT 6:37 PM

SATURNTECH9

MECHANIC
30,869 POSTS

Even though the service light has not come on I still would like you to go to a auto part's store like auto zone and have the car scanned for code's and if there are any bring me back the number's.I want to ask you did you replace the throttle body because of your idle concern?Now on the throttle body the smaller sensor that line's up with the throttle plate shaft is your throttle postion sensor. The lower one which is bigger and look's like a little motor that's your idle air control valve. What that does is move's it's plunger in and out to make a controled vacuum leak to adjust your idle. If it get's carboned up or stick's it can affect your idle. You could even have a bad coolant temp sensor that can mess up your idle as well. Let me know what you find.

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Sunday, June 6th, 2010 AT 8:38 PM