Odd sputtering and rough idle Options

[Malek]

I know the 3SGTEs are notorious for destroying distributor caps and rotors and plugs, etc. but from what I read on here and other forums about this issue doesn't seem to quite match up to my issue.

Symptoms:
-Cold start: idles high normally
-Once warm: idles rough (misfire) and fluctuates 750 - 1000 rpm
-When driving: Major hesitation up to about 3k. Sounds of misfire.
-Above 3k at steady throttle, seems to run fine
-When giving good amount of throttle, doesn't pass 5-7psi and replicates video (below)
-Wideband reads 15ish when above is happening

A comment in the video said they changed their spark plug wires on their GST and it went away..however, this Evo is boosting pass 20psi and I can't get past 7..


Evo 8 Boost


Any suggestions before I jump into dizzy, wires, plugs..? Thanks!

[BonzaiCelica]

ok so bump. i'm pretty sure its the Idle Air Control valve. but just to make sure. here are my symptoms for the 3sge beams redtop motor

Upon Cold Start up: sometimes it will idle/sputter from 1,000-1300 rpm range.(normal idle for all celica's upon cold start is 1300 rpm for the first 30 sec). if it does sputter and have hard time staying at 1300 rpm all i have to do is drive it for 7-10 sec and then put it back into nuetral while the engine is running and the sputtering will go away.

I give it full throttle up to 7,000 rpm for anywhere up to 5-7 sec and then suddenly drop it into nuetral it will idle down to 500rpm and then the idle will die out after 3 sec.

if i'm slowly downshift from 5th to 2nd gear while coming to a complete stop. the idle will fluctuate from 500-700 rpm two times and then go up too its normal 800 rpm idle.

i know you can replace IAC or clean them. i replaced my spark plugs 15,000 miles ago with ngk iridiums...

This post has been edited by BonzaiCelica: May 28, 2013 - 2:00 PM