Could be the loping is due to the ECU cutting fuel to the injectors from time to time due the high idle speed. The unplugging/plugging in the TPS would point to this, as with TPS unplugged, there is no idle indication as there is when it is plugged in. Not sure why the idle is set so high.
When I first got my 22RE running after installing a new cam, it was a somewhat loping and fast idle. Spent hours looking at things and one day a buddy came over as I was working on it. He asked me why I was missing a bolt on the back of the EGR where it attaches to the intake. I guess with the rough initial idle that bolt had backed itself out and was now causing the sort of loping idle. But in the mean time, I had been going through every sensor and device with the assumption it was bad and then I proved to myself that the device was working properly.
I took the throttle body off this morning and thoroughly cleaned it, taking the TPS and IAC valve off as well. I made sure everything was clean and the the IAC valve was working by putting it in some boiling water. All vacuum and air passages were blown out. Put everything back together and fired up the engine. There is no change.
I verified that indeed there is no miss in the cylinders when I unplug the TPS. Unplugging the ECTS did absolutely nothing, whether the engine was cold or hot.
And once again, the idle kicked up to 1500 on startup. After a minute or two the O2 sensor started oscillating. That's normal behavior. But as soon as the thermostat opened, the surging idle started while at the same time the O2 sensor quite oscillating. I don't understand why the O2 sensor does that. It only oscillates again after I depress the throttle.
I haven't checked the AFM yet, and I will do that. I'm wondering if my next step should be to check signal voltages to the ECU. In particular from the ECTS, TPS.
Oh, and I did check the EGR valve. No bolts are loose. <img src="/forums/images/graemlins/lol.gif" alt="" />
