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Check the ECU coolant temp sensor and also the cold start aux. air valve to make sure it is working properly. And double check the TPS IDLe-E2 setting, both at the TPS connector as well as back at the ECU connector to make sure that is right. If that is off, the ECU is in "run engine real slow" mode instead of "nice smooth idle" mode. There is a difference.

While the intake was off, I did verify again the TPS setting. It's good. Here is another nugget. When I let off the throttle, the idle goes low and then creeps back up to 900 rpms and settles in. Any idea what may induce this? Crawler, I really appreciate your thorough knowledge and firmly believe we'll get to the bottom of this. Thanks!

'86 4x4 SR5 22re 5" lift 35" BFG's and 5:29 gears.
'05 4x4 DC Tacoma TRD Sport