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3,000 RPM idle Problem!?!

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ZacTsi

10+ Year Contributor
47
0
Apr 10, 2012
MoscowMills, Missouri
Hey guys I've been avoiding posting this due to the MILLIONS of people with simple idle issues, so I've been working on this car, researching and reading forums everyday for hours. Im Stumped now :ohdamn:

Heres the issue: My car will idle at 3,000 rpm. If I adjust the tps I can get it lower to where it is 1,500 rpm then surges to 2,000 and back down rapidly repeating. But I cannot drive like that because the TPS is so out of line the car will "buck" and thinks the throttle is all over the place. So heres what I've done to try and fix it:

I got a hard pipe intercooler kit from punishment racing w/greddy type s to eliminate the possibility of boost leak on stock i/c pipes.
I rebuilt the throttle body new shaft seals,biss,ect ect.
My iacv was bad I replaced that and tested the new one(new o-ring aswell).
I bought a brand new TPS.
I did a vaccum/full emissions delete/egr block off. bypassing the FIAV.
I replaced my o2 sensor which turned my cel off :thumb:
And the only other mods to my car is 3in exhaust(downpipe/Cat back) and removed the boost solenoid restrictor.

I've been studing my haynes and researching for weeks now. Any help would be greatly appreciated!! After I rebuilt the throttle body and changed sensors the idle just got worse. :barf:
 
Ok just like the other post more than likely it's a vacuum leak or hoses are not in the correct place. Check the idle screw to see if thats leaking or try to turn the screw to lower the idle. Check intake gasket on the throttle body and intake. If that doesn't work sometimes getting a mechanic to help might save you time and money in the long run. I'm always trying but these cars are temperamental and with the idle there are so many things especially the older they get.
 
i had the same problem on my 420a mine would get stuck at 4k tho. so i dont know if it would be the same on your car but i had a bad map sensor that tested good. the ecu was reading it wrong some how so i bought a new one and cleaned the iac and it stopped doing it.
 
Yeah my TB rebuild kit came with a new BISS so i put that in but my buddy ended up breaking it bein to rough with it.So I might be leaking from there. They should of made these in stainless steel! But yeah I have a vaccum delete so hardly any vaccum lines and they are all good. I was wondering if it could be the map sensor! I thought that wouldn't make that much of a difference though but maybe I should try it. And Ill give that crank angle sensor a look too.

And also yeah my base idle set screw doesnt make much of a difference. It stays at 3,000 rpm with it all the way in or all the way out. The only way I can get it to change is if I move the TPS.
 
Im having the same idle surge issue... it idles hight at about 1500 and after the car warms up it starts surging back and forth from 1500 to 2000 (started after i got ecmlink) but even without ecmlink its always had surges. Ive gotten to the point where i just wanna take a bat to it but its too damn beautiful for me to pull through with it LOL can the maf cause it to surge at certain temps? Any info would be highly appreciated.
 
Yeah I know exactly how you feel! ^^ The only I havent replaced is the maf and the intake manifold gasket. Im gonna try the intake manifold gasket this weekend.
 
If you do a boost leak test and it still happens to be doing the same thing, check your throttle cables. That happened to a friend of mine and it turned out it was his throttle cable. Replaced it with a non cruise one from JNZ and it runs perfect now.

My 92 Laser used to idle fine, then jump up to about 2500 and stay there. Turned out to be I had the throttle cables too tight.
 
my car was idle surging when i got it, running seaform through the engine and intake, then throttle body cleaner got rid of it.
 
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