High idle only in park and neutral

[mphillips_90]

Working out the kinks of this 4runner.
Sometimes it'll idle below 1000rpm when in park and neutral but most the time I can expect it to be between 1000-2000. While in gear it's pretty perfect around 750.
Thought it was probably the tps so I put a new one on but nothing changed.
Throttle body doesn't get caught up and it's clean. No carbon rings were on it. MAF sensor has been pretty thouroughly cleaned. My next step is to use a bunch of seafoam and see if it helps.
Any thoughts?

 

[Black798]

It could be an issue with your coolant temp sensor. If it isn't reading properly and thinks the motor is cold it will bump up the idle when your not in gear. I believe that there are two sensors, one for the gauge and one for the computer.

 

[mphillips_90]

thats interesting. never thought about that

 

[alumarine]

Is there a dashpot on these motors?
If so, it might not be allowing the throttle to return enough.

 

[Black798]

I believe there is a dashpot. I saw a post a few weeks ago where someone was having issues with the throttle body not returning. I think they ended up just fixing it with a bungee cord to help the return spring

 

[tvpierce]

I presume you know this, but just in case: if the A/C or Defrost is on, the ECU bumps up the idle.

What year is your truck?

 

[mphillips_90]

its a 98. 310k on the motor. Does it regardless if its in ac or not. dashpot is a new one for me. Can you explain?

 

[Black798]

1999 SR5 4x4 5VZ-FE idling low when warmed up - Page 3 - YotaTech Forums

New ECT sensor made noticeable difference - YotaTech Forums

Gives these two a read. There are a few tests you can do that are explained in the first link.
Hope this helps

EDIT:
http://www.toyota-4runner.org/3rd-gen-t4rs/123396-my-high-idle-cured.html
This also might help

 

[dogtail]

Sounds like throttle body issue, happened to me on a high mileage 3rd gen throttle body swap. Try this cheap fix perhaps. http://www.toyota-4runner.org/3rd-gen-t4rs/123396-my-high-idle-cured.html

Working out the kinks of this 4runner.
Sometimes it'll idle below 1000rpm when in park and neutral but most the time I can expect it to be between 1000-2000. While in gear it's pretty perfect around 750.
Thought it was probably the tps so I put a new one on but nothing changed.
Throttle body doesn't get caught up and it's clean. No carbon rings were on it. MAF sensor has been pretty thouroughly cleaned. My next step is to use a bunch of seafoam and see if it helps.
Any thoughts?

 

[alumarine]

its a 98. 310k on the motor. Does it regardless if its in ac or not. dashpot is a new one for me. Can you explain?

A dashpot is like a shock absorber for the throttle return.
When you take your foot off the gas it causes the throttle to stay open a bit before letting it return to it's normal idle position.
It's an anti pollution thing.

I just checked on my 2000 and I don't have one.

 

[Jramos13]

Im sorry for reviving an old thread, im new to the the 4runner but not new to offroading or working my way around engines.

Yesterday i bought a 99 4cyl 4runner 2wd with 108k miles on it, the engine is strong and it has no problem keeping at 75mph on the highway, however it will idle at 1100rpm, when the car is in P, N or stopped. I connected my ob2 tool and otice that the ecu is in open loop mode and the collant engine temp is at 154 +-5, however is not throwing a CEL

 

[GioNazT4R]

I have similar issues. Took it to auto zone and a threw a code regarding the coolant temperature sensor? What's the issue????


Sent from my iPhone using Tapatalk

 

[phattyduck]

Im sorry for reviving an old thread, im new to the the 4runner but not new to offroading or working my way around engines.

Yesterday i bought a 99 4cyl 4runner 2wd with 108k miles on it, the engine is strong and it has no problem keeping at 75mph on the highway, however it will idle at 1100rpm, when the car is in P, N or stopped. I connected my ob2 tool and otice that the ecu is in open loop mode and the collant engine temp is at 154 +-5, however is not throwing a CEL

154*F is still in 'high idle' territory. It should be 180*F+ in normal operation. Maybe the thermostat is stuck open slightly?

-Charlie

 

[Jramos13]

Well i just replaced the thermostat to the corrext 180 and after a few minutes the idle dropped to about 700 but the gauge was a bit to the hot side but never got hot, i drove it around but after a while the tenp got down to 160 and it stayed there, and now im at 900rpm while on drive and stopper, and at 1400 while on P and N

 

[Guy Bri]

Hi all. I currently have a 98 4runner 4x4 W/rear diff lock, auto, with over 560,000 kms on it. I'm having an issue with a high idle. In park & neutral it idles around 950-1400. In drive it idles around 750-800. I don't have any CEL. Outside temp is around -18c and colder. Here are things i have checked and done to try to solve it.

Cleaned MAF.
Removed and cleaned throttle body and IAC. (Checked the IAC works.)
Sea foam through the intake.
Cleaned the PCV valve.
Checked to make sure the throttle cable isn't too tight.
Can't find any vacuum hose leaks.
I have tried the spacer trick at the back of the throttle mechanism.

Any ideas? I'm thinking coolant temp sensor?