Idleing at 2K RPM then car warms up then pulses from 2k RPM and down to 1k RPM?!?!?

[ECLIPSE95]

ok I have had a high idle problem for a month now and I still haven't found a solution to the problem and I have already read up on Idle stuttering and whatnot and I have already checked all of that...my CEL light comes and goes now...but lately my idle seems to be getting worse..I have already replaced a leaky vaccum line and that didn't help..I took it to a mecanic twice and he doesn't know how to fix it...a friend of mine sprayed carb cleaner in certain spots so see if anything was leaking..he sprayed it by the intake manifold and it flooded the engine kinda of then he sprayed down where the intake manifold and head connect and it seemed to suck the carb cleaner in an flood the engine but it didn't do this anywhere else..it only did it by the number 1 cylinder....so I bought a gasket kit and injector Orings to get those intake manifold gaskets replaced...would a leaky intake manifold be cause this problem from the gaskets being bad?..but I am sure the gaskets are new because I had head work done on my car and all of the gaskets where replaced last summer....so would replacing the gaskets in the intake manifold help my harsh Idle?...it seems to be getting worse now I just stop at a stop light and it pulses from 1k RPM and to 2k RPM and it keeps doing that..no matter what I do...I am in need of some help...thankz..~Dustin

 

[NOSNUSE]

A leaky intake gasket would cause this problem, also try and unplug the vacuum line from the EGR valve and see if that helps, do this after the car has warmed up. Also you might want to check the TPS and see if it is getting the correct amount of voltage. Hope this helps you out man.

 

[ECLIPSE95]

Ok I pulled the vaccum hose from the EGR valve and that didn't do anything still pulses...I will check the TPS voltage...what is the voltage that you want on the TPS? can I check the voltage with OBDII? but I wouldn't know what voltage to look for? and if that doesn't help then I guess I will have to take out my intake manifold and replace those gaskets but I am totally sure those are new..but I guess then can just develop a leak...

 

[1LE]

BISS still intact? (Mine did that when the BISS blew out)

Check the ISC?

 

[TargeT]

here's your fix

sell it and buy something with a turbo


other than that, check very closely for vacume leaks (either via intake, or tubes. a spray bottle is a good tool for that, you can h ear the water being sucked in)

 

[ECLIPSE95]

well this is my daily driver car and yes I was planning on buying a turbo'ed DSM but I can't afford it when I am going to college but when I get out I wll be buying a EVO8 and a Second gen GSX...but for now I like my RS..it still beats honduhs

anyways I had a friend already spray carb cleaner and it did get sucked in by the intake manifold and the head..I think the gasket is shot..even though its new..

as for the TPS I still don't know what is the correct voltage for it?...how do I know if its bad??

 

[SpeedFreak03]

I'd say the ISC/IAC (Idle speed controller/Idle air controller, same part, 2 diff names) is the culprit. I don't know much about 420a's tho, but I know for 4G63s thats usually the problem. Try this procedure: http://dmtalon.v8eaters.com/ISC.html

Your ISC may be located in a different spot but if you can find the ISC then test it the same way.

 

[Projectpat115]

There is a plug in the back of throttle body that makes your rpms jump. make sure its plugged in.

 

[ECLIPSE95]

actually i fixed it when i replaced my transmission at the shop..ends up that the intake manifold gasket was falling apart and pieces of the gasket was fallin off..and it keep on going to higher RRM...but once I replaced the intake manifold gasket the car idled just fine..no stuttering anymore..I hope this helps for future problems with high idle sorry i didn't post this earlier...

Stuff I went through to fix this problem
1.Spark Plugs and Wires- to see if oil is on them or if they are in good condition
2.Throttle Cable-check to see if it was tight or caught up on somthing
3.Throttle Body-cleaned that whole thing out to see if it was being stuck open
4.TPS-checked to see it voltage was out of range which it was but not bad, replaced it anyways
5.Replaced vaccum lines
6.Intake manifold gasket-(took me this long to figure it out) replaced gasket,fixed problem