Toxin

iTrader: (2)

So I've got my own idle problem nowadays and here it goes:

Stock 06 Evo IX, USDM running on EU 100 octane (about the same as US 93 I guess). The car idles fine during warm-up and slowly as it gets warmer reduces it's rpm. Then it gets to a point where the idle starts dropping from 900-800-700-600 and at about 550 the cooler fan turns on, car bucks slightly and the idle jumps back to 1000, cooler fan turns off and the car repeats the process.

The process goes slowly - takes about 30-60 seconds for this process and it's a loop repeating itself.

I've replaced the ralliart drop-in filter with a stock one (only mod the car had for a few days) and the car is now completely stock on a stock map. Idle is set at 9xx and it simply keeps dropping.


What could be the possible cause of this?

(I've already reset my idle trims, checked for boost leaks and the car is running a stock IX metal bov that is recirculated)

High_PSI

iTrader: (50)

Leaks would do this. Look at the MAF, is it damaged? Is it DIRTY? What kind of aftermarket Intake is on the car? Also talk to 4WS, he can help you as well with some logs.

nikkadanny

iTrader: (31)

Check out your iacv

amui07

iTrader: (2)

I have a similar problem, not exactly, but I've isolated my problem to a vacuum leak.

Toxin

iTrader: (2)

Yea we'll sort it out with 4WS, I just opened a topic so I don't bug him for everything. He tuned my VIII and it's still runing like hell, this car I just bought so we haven't even started to do anything tune related.

Waiting for my mods to arrive, includind the wideband, then the fun starts, but I'd like the car running without any problems before that

High_PSI: The car is on a stock intake with stock air filter on a stock map. I've cleaned the MAF already.

Nikkadanny: IACV?

nikkadanny

iTrader: (31)

idle air control valve, its on the throttle body it could be burnt up..do you have any idle hang at high rpms?

Toxin

iTrader: (2)

No, just standing still idling.

MRJEVO

I'm going to go with a vacuum leak also. Have you done any work to the car lately besides the filter? Make sure the intake connection to the turbo is tight. That is a common area for leaks. It almost sounds like there may be an air pocket also in your cooling system.

FL_SilverEvo8

iTrader: (15)

i would say it is this also. i had the same prob when i was running 93 oct + meth. i took of that idle air control valve and it was melted. replaced it and it runs fine now. do you have a CEL on?

killthelights14

iTrader: (2)

same problem, cleaned the throttle body and all the sensors, cleaning the maf today and ill report back with the results.

Toxin

iTrader: (2)

Killthelights any news?

No CEL

dp310

Any news ? my car today out of nowhere i notice that my rpm was staying at 1100 then i would drive to the next signal light when i come to a dead stop .. the rpm drops to 400 ~500 and it picks back up right away to 1100 and stays
tomorrow i'll be checking for leaks while im doing my oil change ! (oh yea i got the hks sponge filter =[ hopefully i'll put a k&n filter on it asap, oh yea also im on 91 no 93 in cali =[ )

Thanks

High_PSI

iTrader: (50)

I think it is just that your car is eager. It wants to go fast and it is kind of "Tugging on the leash" so to speak. I think you need to let your car run more, I bet you drive it gingerly and it gets very anxious. Let your car run, when it gets tired, it'll calm down.

killthelights14

iTrader: (2)

well i cleaned everything, took apart the throttle body and everything looked good. So i sprayed it all down with carb cleaner, then cleaned the MAF with MAF cleaner, while the air fuel ratios are def more stable according to my UEGO gauge the idle problem is still present. Im going to guess its the IAC sensor and that it needs replaced, i also did a leak test and found a leak in the throttle shaft seal...looks like its coming apart again

V.8MR

iTrader: (6)

vaccum leak/boot leak would be my first guess. Followed by the MAF.