Crazy idle...new info may help...please help

[TurboDreamzGST]

Got a 98 GST, intake, 3" custom cat back exhaust, greddy type rs bov re-cirulated, 16g turbo, boost controller and megan racing o2 housing...i posted recently about my crazy idle that just started happening...when the cars cold its a normal idle around 900-1000 now but than once the car warms up or if its very hot out the idle will jump up to anywhere from 1300-1600 and hold there. Now i just installed my APEXI SAFC2 yesterday and noticed this: when the idle is at its normal range of about 900-1000, the throttle percentage reads 0% on the SAFC but once it gets hot or if its hot out, the throttle percentage will be anywhere from 2.5% to 6.5% causing my idle to be up around 1300-1600. This is leading me to believe that once the car warms up the throttle is getting stuck open. I already opened up the throttle body and cleaned it all out and cleaned the cable and everything else but nothing changed. On my other post, people mentioned that it could be a dirty throttle body, bad ISC aka Idle air control motor, or FIAV getting stuck. I figured with this new info showing up on the SAFC2 it might help to determine what the actual problem is before I go and start buying new sensors. Can anyone help to let me know what it might be please? Please help guys, its so frustrating!

 

[2gdsm_nc]

Bad ISC sticking that is where you are getting your extra flow when engine warms up. It should shut. mine had the same problem and it finally threw the cel code to go with it, it takes it some time to cycle threw before it will throw it.

 

[TurboDreamzGST]

ok thanks a lot man i appreciate it...just so i understand correctly, the ISC is the same thing as the idle air control motor or IAC right?

 

[2gdsm_nc]

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this one, Idle air control valve, Idle Speed Control valve, same

 

[TurboDreamzGST]

Ok thanks a lot

 

[Simadowna119]

i had this same exact problem just a few days ago and i replaced my IPS (idle position sencor) and that fixed my problem, its the black peice on the front of the throttlebody, idk much about these DSMs yet so idk if the 2g has the same peice but if it does i would definatly look into that..... ive been told by many people that all the ISC does is regulate the idle when turning on the headlights, radio, air condition, ect... ive also been told alot of people run there cars without the ISC with no affect on the car except the idle will drop a little when kicking on the AC and such....... I bet its the IPS

good luck

 

[Simadowna119]

whats up with you buyer/seller feedback

 

[TurboDreamzGST]

Well when I first got the car the CEL was on due to a bad TPS so I replaced that n it was fine for about 2 months n now this idle problem started happening just about 2 weeks ago...my buyer/seller rating is like that ### some kid wanted to trade his auto gst for my 5 speed gst about 2 years ago n after diagnosing the problems my car was having said he still wanted to trade because he wanted 5 speed n I couldn't afford to fix my car...after we traded he realized he wasnt capable of fixing the problem with my car n got pissed n started bad mouthing me...turned out his gst auto that he gave me was a lemon anyway n he knew it so once I confronted him about that he backed off n realized that he got the better deal n left me with the sh*t end of the stick