2G: Help .. Idle surge

T Series Boost · 06-01-2011, 07:43 PM

yup, I read some troubleshooting tips and no help. here's the problem

Symptom : Only when it's warm/hot out, and the car has been running for a while, the idle will start to creap up. When it really gets warm the idle will go up to about 1500rpm, and then drop to 900, and back up. in roughly a 3 second cycle. Makes ppl think I wanna race them.

I've disconnected the Idle speed control motor and it (surprisingly) was not the cause. I'm leaning towards the throttle position sensor, but before I get a new one, has anyone ran into this before??
any help appreciated.. the warm weather is just around the corner.

SpoollinAwd · 06-01-2011, 07:47 PM

Have you done a boost leak test?

LiquidX · 06-01-2011, 07:47 PM

Start here.
Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)
Idle Surge FAQ

Also as redundant as it is, do a boost leak test too at the TB.

T Series Boost · 06-01-2011, 08:04 PM

vacuum leak came out ok.. it's leaking a but around the throttle valve.. I dont think enought to cause this, but maybe when it gets really warm it gets worse. and I was following terry's troubleshooting, but it doesnt really seem like my issue. I will try cleaning out the EGR.. a good idea regardless.

LiquidX · 06-01-2011, 08:07 PM

A vacuum leak test is different than a boost leak test. Pressurize your intake tract to at least 20 psi and any leak is a bad leak that needs fixed as all air in the system is metered.

SpoollinAwd · 06-01-2011, 08:07 PM

Personally I removed all my emissions and that cleared up my idle surge Im not saying it will help u but it does clean engine bay and less vac lines to worry about delete that egr.

Greeno · 06-01-2011, 10:44 PM

my Idle surge went away when I re-did the Throttle Body shaft seals, CR 3930, or o-rings