Idling
I tried just about everything. I even spent 8 hours SD tuning. Everytime I thought I had it nailed down, I'd go start it a few hours later & the surging was back. Except the last time when it was fine until I took it to the track. Then it idled like **** again.
So, I gave up & put my TB blade with the big hole in it back on, and that helped. But it still wasn't perfect. I did some logging & found the O2 sensors were reading low, reading down around 200mV about half the time at idle. The Bosch & Denso sites say this is an indicator they are going bad so I replaced the O2 sensors. (they were BLACK) All better now. Even after making over 6 passes at the track.
I know a lot of people here say you don't need to drill your TB blade, that you can tweak the IAC etc & make it idle. We couldn't. We'd do some logging & changed things & it would be better, only to revert back. But I think the O2s are the key. If they aren't reading 600-700 at idle, you're probably chasing your tail trying to tune. The PCM bases a lot off what they read.





