Have an 01 SL1 here, the damn thing idles at about 2500. Can't really detect any vacuum leak, cleaned the IAC, changed the TPS and throttle plate... Any ideas?

 

The idle air control valve adjusts the idle speed while the throttle body remains closed or nearly closed. Check that the throttle body is closed, try carb cleaner spray around the intake manifold to check for a loose gasket as the ide speed will change upon ingestion of carb spray, make sure the linkages are free from binding by working the throttle and cleaning. Examine the PCV valve hose routing for cracks anywhere allowing air entry and check the engine coolant temperature sensor for the right one, brass, and not the older resin tipped one that's prone to cracking and causing high idles.

 

Well, spraying brake cleaner around the IM ports/fuel injectors causes the thing to bog down real bad. The linkages definitely arent stuck i inspected the tb real good so i know its not that. So, should i get IM gaskets since it must be sucking in from there? And change the CTS? Where is that cts on these beasties?

 

If you are able to change the idle from a leak around the intake manifold can you locate the nuts/bolts and try tightening them first? There are models that were assembled with a fold in the manifold gasket and maybe yours is one of them. If tightening the mounting bolts doesn't seal the leaks then of course you must remove the manifold and find the cause of the leak. Ordering a replacement gasket is a good idea if the original is damaged from removal.


The coolant sensor is located under the EGR valve and uses a two-wire connector. The old one is resin tipped and prone to cracking while the replacement is brass. Replace the connector if its corroded either from a junk yard air temperature sensor or the dealers $30 part.

 

If you figure this out, please tell me or least keep this forum updated. I'm having the same problem (but only at 1900). I just got a new readout today. P0122 which is the TPS. So I'm probably going to take care of that next. It used to (and still does occasionally) get an error about my MAP sensor so I replaced that as well...


Do you have access to an OBDII reader? Or a better question would be whether or not your check engine light is on...

 

Yep, CEL says IAC i believe. Well i'll check it out this weekend and let you guys know, thanks for the help!

 

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