So my engine had been idleing to low for a little while...like 550-650 rpms...so i moved the throttle cable up a little bit so it idled a little higher...also when it idles this low..my oil light comes on..does anyone have any idea what that could be?.....but anyways...fixed the idle..it was good for about a day...then went back down...a couple days later my service engine light comes on..so i bring it to autozone so they can check the code...and it says my idle is set to high...even though it is still idling at 550-650...how do i fix this?...is there some sort of throttle sensor and since i moved it it thinks its higher than it actually is???

 

check if you have any vacuum leaks post MAF. Adjusting your idle using the throttle cable is not the way to go. You obviously have a problem so i would try to cure it first rather than hide it. Try disconnect the battery for ten minutes then relearn the ecu. Also you auto or manual?

 

i have a manual...relearning the ecu will only get rid of my service engine light though right?

 

The CEL probably went on because of the low idle and lack of oil pressure.
How high did you set the idle anyways?

 

only set the idle up to like 750....making sure the oil light wasnt coming on and it was idling at a good rpm...didnt last very long and it was back down again

 

A bad ground will cause a low idle. Did any grounding wire kit install recently maybe? Or maybe you might have loosened a ground bolt up when you worked on something?

 

Try this reset ECU, put the throttle cable back to where it was. Start up the car and adjust the BISS screw to control idle from memory turning it anti clock wise increases idle, set to factory 800-900RPM.

I believe the oil light comes on when the idle drops too low since its nearly going to stall. Im assuming your car has a 4G94 SOHC 2L

its a 4G94 2L yeah? If so why dont you adjust your BISS screw you might have not noticed because its usually covered with a plastic cap to prevent dirt and muck entering.

The oil light comes on cause it almost going to stall, from experience most mitsu cars as far as 4g lancer/mirage do this when there at near stall. Try the above and tell us what happens then we try somethind diffrent.

 

Thanks for all the help...im definatly going to try that then...ive noticed when i leave my car idleing that if it sits there for a couple minutes..every once in awhile it will randomly go up a couple hundred rpms for a second....is this normal? its done it for along time..way before any of this happened..just wondering if this is unusual or not.....i will let you all know if my problem is fixed as well..im hoping thats whats wrong and it sounds like thats what i need to do to fix it....thanks again everyone

 

Hmmm have you ever cleaned out your TB ever since you purchased your car?

That sounds to me like a ISC motor problem, try to clean it out with throttle body cleaner. Allow to dry which usually does not take long and test it out, then adjust the RPM accordingly from the above steps i quoted you.

 

i havent cleaned out my throttle body before..so that sounds like its a good idea to me..im going to work on this either tomorow afternoon or on saturday afternoon depending on when my dad is available to give me a hand...once again thanks for all the help....has this happened to you before? (llt-racing)? just wondering how u knew how to do this..b/c it doesnt seem like a very common problem to me

 

It has happened to me before and the cuplrit was a dirty ISC motor, you will know what i mean when you spray it out with throttle body cleaner. Make sure you get TB cleaner not carby cleaner, sounds silly but some carby cleaners are harsh and not recommended by mitsubishi.

Worst case scenario it would be damaged BUT that is highly unlikely, if it is damaged just get a 60mm TB from DSM/montero make sure you get the connectors with it if you do both on ISC motor and TPS that way you can cut your original 4G94 ones out since they are diffrent and hard wire the DSM/Montero connector on.

 

Alright i will be working on it tomorow afternoon...bought some throttle body cleaner today..hopefully it will be all fixed and working good..thanks for all the help again..will definatly let you know if it works good..thanks again

 

Any word BerIce? Ive had a similiar problem and Ive went around in circles trying to figure it out. I think part of mine was I was having multiple problems at once. My o2 sensor went out and Im having this rough idle issue. Cant figure it out though. cleaned the throttle body. A TPS is outrageous! Cant find one at a junkyard that fits. apparently the 4g94 is kind of an oddball motor.

 

You probably need to adjust the idle values in ECUFlash as well as reset the BISS adjustment. To correctly set the BISS, you should use the SAS mode in EvoScan to lock the stepper motor.

When you adjusted the cable, the ECU adjusted the stepper to lower the idle back to the set value in the ECU. that's why you got the high idle CEL ... the ECU was applying max adjustment down to compensate and that trips the code.

 

Yes he pm me and he said the problem has improved other than that not much further details.

To be honest adjusting using evo scan should not be necessary specially if the car did not develop this problem in the start. Simple testing should fix it like cleaning out tb/isc motor, setting voltage of tps and perhaps condition of 02 sensor. Sometimes also the mitsu ecu's have a good life expectancy of 10 years then there caps start wearing out. This problem is most common with in the 4G92 mivecs and 93 SOHCS.