My '91 2wd automatic hits about 1500 below ~65 ambient cold start and settles to 875 within a couple minutes. Above about 65F, starts and idles at about 1000 and drops to 875 within a minute.
The 4Runner, '88 manual, was only a little bit different with cold idles below ~65F peaking around 1600, regardless actual ambient temp, then settling to 825 within a few minutes with the time increased with lower ambient temps.

Cold start parameters are compensations to hot-engine parameters, not hot-engine compensations to cold engine operation, so proper IACV operation requires adjusting idle speed and ignition timing with the engine fully warmed up- setting things in accordance with the under-hood sticker, not some forum poster telling you to use XYZ degrees and ABC RPM. Issues with cold start then become more easily isolated to the appropriate components, those being predominantly the IACV or ECU coolant temp sensor and to a lesser extent the cold-start injector and time-switch, fuel pressure pulse dampener and/or regulator.

 

to be clear, i'm not recommending any course of action; i'm providing data points to the OP as to how my '87 22re handles cold starts. when warmed, the idle is steady at 750 rpm no matter the ambient conditions or weather.

wally

 

26* overnight. started up, idled briefly @ 750 rpm, then gradually went up to 1050-1100 rpm. after about 3 minutes, idle dropped down to a steady 750 rpm.

all of this without once pressing the gas pedal, either before starting or once running.

 

Someone is mixing coldstart with the warm up enrichment program, similar but not the same.

Coldstart is the extra fuel squirt from the CSI.

Warm up enrichment is extra duration applied to the primary injectors.

Idle speed a function of the idle air valve and its reaction to either water temp or current sent by the ECU.

Sorry I have no data points for you, I don't go out when it's chilly.

 

This is an interesting point...I was not sure if the ECU sent current to the idle air valve to heat the coil and open the valve or if the valve just opened with h20 temp increase and the R of the valve coil fed back to the ECU as an input to tell the ECU how far open the valve is.

 

I think i nailed it! finally had a fast idle on cold start tonight after disassembling/studying/testing/adjusting the aux air valve. Will try again in the morning to see if it's consistent and then post my details.

 

Same way I figured it out. Once that front plate was off the i.a.c.v. and it goes through a cold/warm cycle it becomes obvious how it functions. Glad you got it worked out. I'd bet a faster idle during first start at ambient outside temp (even on a warm day) allows oil pressure to rise and the engine to warm up faster. Both good things.

 

Yeah, just posting to confirm now that we've had some pretty cold nights in the 30's and 40's, the truck does start and fast idle around 1100-1300 rpm climbing to that RPM after about 30 seconds. It stays there a few minutes then drops gradually to the warm idle speed. I tested/studied the IACV closely off the truck and got a slight adjustment out of it, to make certain it closes completely. That is what made the difference in operation.