At initial startup when cold it idles with with 8psi vac (according to greedy ebc) or -15in/hg and then after it warms up and I drive it the idle becomes loppy and the vacuum is anywhere from -10in/hg to almost 0 (this is diffent almost every time... but in the same range) sometimes it will be idleing like shit then after 10-15 seconds it will smooth and be perfect... Tonight it was so bad and around 500rpm with no vacuum so I turned the car off while i waited for the light, 30 seconds later i started it up and it idled beautifully. It actually got worse after I disconnected the battery. Could this be egr related? i've checked all the hoses coming off the intake mani. I am just confused b/c it idles perfect sometimes but most of the time (after warm up) it idles terrible. When its cold it always idles perfect.

Also it seems to drive fine... I searched and i found none that described the idle being good sometimes and shitty others... but the timing was what most people said for the bad idle symptoms but i don't think that can be it because sometimes it idles fine. The egr is not blocked off and for over a year i have had a cel for insuficient flow... I will be blocking it off within the next week or two but do you think that could be the problem?

I replaced/gapped the plugs, replaced the iac vavle, cleaned the throttle body, and replaced the throttle body gasket. I also replaced the tiny filter in the missing link... the inside of the throttle body was COMPLETELY covered in carbon build up.

Evo 8 - 12.3@113 circa 2009 (~330whp)
Now with BB Xona Rotor HTZ FP Red and ~450whp
2018 MSM Civic SI Ktuner TSP stage 1 w/ Honda hacked headunit.

could be the egr or the evap yea, disconnect the egr and evap entirely and see what she does (remove the evap line on the top of the tb) and disconnect the egr solenoid

sounds like an intermitten vaccum leak or something to me

edit: i was having idle issues when cold, it ended up being an evap leak back by the gas cap...go figure. the system purges the evap line when first started, so it essentially had a vaccum leak and acted just like one. i always make sure and click the gas cap twice now, replaced my egr from the parts car, byebye flow code...byebye lame intermitten idle.

edit: whats your upstream 02 sensor cycle at when warm? should be between .2 and .8 V....if not your 02 sensor is toasty, and that would cause it to idle rough when warm. just a thought

_ _ _ _ _ _ _ _ _

96 Black ESi
91 Red TSI AWD (RIP)
02 WRX


"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"

Aerospace Certified TIG welder for Precision Castparts in Portland, OR.

JoshSpair.com

According to the apexi TT the afr is in the high 13's and 14's (it constantly fluxuates... 42# and sfmu...) the volts also are between the ranges you specified, it is constantly changing between .2-.8

EDIT: when i was checking I completely forgot to check the evap even after I went out to my car specifically to check that... i'll do that tomorrow.

The method I used to check the other hoses was to just use pliars and clamp them individually and check for change in idle... no change occured.

EDIT2: also its hard to check because sometimes it fixes itself after 15-20 sec or so or it'll just stall... so i never know if it fixed itself when i am checking or it will just stall while i am trying to check the hoses...

Evo 8 - 12.3@113 circa 2009 (~330whp)
Now with BB Xona Rotor HTZ FP Red and ~450whp
2018 MSM Civic SI Ktuner TSP stage 1 w/ Honda hacked headunit.

the motor randomnly opens the EGR and sometimes it closes off the IAC entirely and relies on EGR gas for its idle air...my thoughts are that since your egr keeping throwing the flow code, its not supplying enough air to the motor at idle when the ecu decides to not use the IAC....

know what i mean?

_ _ _ _ _ _ _ _ _

96 Black ESi
91 Red TSI AWD (RIP)
02 WRX


"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"

Aerospace Certified TIG welder for Precision Castparts in Portland, OR.

JoshSpair.com

Yea, But when you block it off it would have the same effect as it not flowing and I thought that if it can't get enough air through the EGR to idle correctly the ecu was supposed to scratch that and go back to using the IAC...

But this shitty idle occurs 80-90% of the time, its just the other 10-20% is when it fixes itself or doesn't do it at all... its pretty persistant. But I still have a few things to try like the EGR, evap, and wires (thought the wires would be related to it never idleing or running right at all though... thats how it was last time my wires went bad, it wouldn't do anything without bucking and stuttering)

More on this after I mess with those 3. thanks for the help turby

Evo 8 - 12.3@113 circa 2009 (~330whp)
Now with BB Xona Rotor HTZ FP Red and ~450whp
2018 MSM Civic SI Ktuner TSP stage 1 w/ Honda hacked headunit.

yea but when you block off the egr, the ECU throws a code and it will no longer try and get idle air from the EGR

_ _ _ _ _ _ _ _ _

96 Black ESi
91 Red TSI AWD (RIP)
02 WRX


"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"

Aerospace Certified TIG welder for Precision Castparts in Portland, OR.

JoshSpair.com

OH, ok well I hope that fixes my problem then...

Evo 8 - 12.3@113 circa 2009 (~330whp)
Now with BB Xona Rotor HTZ FP Red and ~450whp
2018 MSM Civic SI Ktuner TSP stage 1 w/ Honda hacked headunit.

EGR block off kit fixed the problem thanks everyone who helped

Evo 8 - 12.3@113 circa 2009 (~330whp)
Now with BB Xona Rotor HTZ FP Red and ~450whp
2018 MSM Civic SI Ktuner TSP stage 1 w/ Honda hacked headunit.