hey ive been reading all over the forums and im thinking that i need a new iac but now i guess i just wanted everyones opinion before i go spend $300 at the dealer for a new one. ive got an 03 evo 8 that doesnt like to start up when cold. when its cold out (say less than 55 degrees) the car starts up fine then dies right after. so i have to put my foot on the gas a little to keep it idling (usually around 1200-1400 rpm) for about a minute then let go of the gas and then it idles around 400-500 rpm. when its fully warmed up it will idle fine around 850-900 rpm. when the AC is on, the check engine light will come on reading "idle rpm lower than expected" now when its warmer out, it will start up around 400 rpm without holding gas down and then continue to run fine after its warmed up. also when downshifting sometimes the idle will want to bog down to like 200-300 rpm and want to stall. im thinking its the idle air control valve and not a computer problem. ive never messed with the idle screws and when i got tuned (it had this problem before the tune) the guy tuning me said my MAF was reading correctly. Any Ideas?

 

bump

 

bend over and suck it up.. your IAC sounds like it's bad. another symptom to check would be the AC idle speed. if the idle doesn't rise like it should, then chances are your IAC is bad.

While you are in there I would also recommend replacing your throttle body shaft seals.

 

yeah when i turn the ac on when idling the idle goes down. i guess im headed over to mitsu for a new iac. thanks

 

there are 2 things you can do, easiest is to mess wiht your biss screw, turn it out about 1/2 or 3/4 or 1 turn. start with a 1/2 turn & see how things responsd.

i will tell you now, MOSTLY everybody will say this is a no-no, the earth will blow up, etc.... I own a 03, i did this about a week after owning the car new...never had a problem since.

Here is where the biss is located:



use a short length, normal size headed flat or phillips head screw driver ( i prefer a phillips) & turn counter clockwise......your opening a hole to allow a little more air in straight away without having to jack with the throttle.

just remember how much you back the screw out, so if you have the sweap out iac's, you can go back to the o.g. setting.

are you running meth or had any major backfires? this may have damged your iac if so.

good luck


i have a used 03 iac i can selll you for $50- shipped within lower 48 states, including paypal too if you need to.

it takes about 15 minutes to swap iac's.....oh yeah, your also allowed a 10 minute break during that time-frame!

its easy to do, jst need a stubby/short phillips screw driver. if your iac can use a 7mm socket, then you most likely have the later :top-hat" designed iac......i dont have spares of those.

pull your iac & post a pic of the part that points/lives inside the tb.

 

not running meth or have had any backfires that i know of. when i bought the car it was running this way...the kid before me said it was cause of the weather. stupid me believed him. ill try that idle screw thing and let ya know how it goes. if not too good, then i may be paypaling you $50. thanks

 

dude- if this is a modded used car.....im not sure where you should atart......just remeber the basics.

 

arent there cold start maps for this car? although i doubt those have been touched. im headed to work but i will try that screw before i go

 

yeah i tried using that iac screw. it did nothing. i turned it 3/4 of the way and tried a full turn. in fact it seemed like when driving with the screw turned out, the car was actually slower but maybe its just me imagining things lol

 

bump

 

I had a problem like that a couple years ago, it was a bad boost leak at my intercooler coupler. Have you ever checked for a boost leak or a vac leak?

Also Aby@MIL.SPEC selling you a used IAC for 50 bucks is a good deal if you dont have any leaks.

 

i have meth and my car idles rough to start. Tried a 06ix iac valve, no luck...same issue,however, the configurations are diff from the 03/06evo. parts say they are the same, but they dimentions are different.

I have cash ready for the IAC off the 03 evo ABY.

 

the iac is already sold to me evoryder...sorry. thanks again ABY for the IAC. hope it fixes my problem. the car stalled the other day coming to a light with the AC on