Slow Idle/near stalling on startup

H

HeelsFan72

New member
2018 SR5, ~41k miles.

Read a bunch of threads with similar but different issues- posting here in hopes of some help.

Recently I started noticing an issue when cranking up my 4R. On cold starts, it will crank strong, engine starts, then for a split second it kind of lugs down and the RPMs drop. Almost like it's going to stall, but doesn't actually get there. After that first initial drop, RPMs come back up and it idles fine. If I shut the 4R off immediately and crank again, there's no issue. Battery seems fine, and I feel like it's too new to have an alternator issue, plus if it were, it should happen every time I figure.

Does it regardless of fuel level (this morning was half a tank), but wondering if it could be something with fuel pressure on startup? Also wondering if it could be a MAF issue? Haven't noticed any issues while driving, throttle response seems normal, no idle issues when stopped at lights, etc. Just this weird startup issue. No lights on the dash.

Any help is greatly appreciated.
 
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Not sure if it’s common with this engine, but with a good throttle body cleaning or induction service sometimes an idle relearn is required, usually depends on how dirty it is prior to cleaning
 
08TxRunner said:
There isn't one.
Click to expand...

There has to be a way to control the idle speed. According to the factory repair manual (TOYOTA 2016-2019 4Runner Repair Manual RM27F0U) the throttle body does have a "throttle actuator" motor in it for that purpose, whether you call it an idle speed control motor, or a throttle actuator motor, it doesn't make any difference.

The trouble shooting procedure for low or unstable idle speed is shown on page 3280 of the factory repair manual.

Procedures for cleaning the throttle body start on page 3786 of the factory repair manual.
 
The ac compressor cycling if the defrost is on or any aftermarket accessories amp draw at startup. If you are still under warranty you can have the dealer check it out.
 
fkheath said:
There has to be a way to control the idle speed. According to the factory repair manual (TOYOTA 2016-2019 4Runner Repair Manual RM27F0U) the throttle body does have a "throttle actuator" motor in it for that purpose, whether you call it an idle speed control motor, or a throttle actuator motor, it doesn't make any difference.

The trouble shooting procedure for low or unstable idle speed is shown on page 3280 of the factory repair manual.

Procedures for cleaning the throttle body start on page 3786 of the factory repair manual.
Click to expand...

It does make a difference because there is no IAC motor on the throttle body, which is what you told him to look at. Idle is controlled by the same motor that actuates the throttle blade.
 
fkheath said:
There has to be a way to control the idle speed....the throttle body does have a "throttle actuator" motor in it for that purpose, whether you call it an idle speed control motor, or a throttle actuator motor, it doesn't make any difference.
Click to expand...

I'd agree with you, but then we'd both be wrong. The throttle actuator motor's purpose is to...actuate the throttle blade in response to either accelerator pedal input (via the ECM) or ECM-controlled engine speed inputs. Much more than simple idle speed control as you proposed.

With that said, fully agreed on cleaning the throttle body (and MAF using specialized MAF cleaning spray) as next steps.
 
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