High Idle when warmed up

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Gerdo said:
My idle is about 1000-1100 rpms even after the engine is warmed up.
What would cause this?
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Have you worked on the rig recently? A loose vac hose or electrical connection can do this. I had an 1100 idle for three months because the vac hose to the throttle opener thing on the front of the TB was sitting on the nipple, but not PUSHED on. Looked perfect, I only found it because I went to clean the TB to try and fix the problem. Once I realized the hose had been loose, I pushed it back on and...instant free fix. My favorite kind.
 
Check your IAC Valve. Happened to me weeks ago when finished replacing both head gaskets. Put everything back again and at cold start, idle was too low and then as soon it was getting hot, idle started to get higher till 1100 rpms. Opened and checked it and found it was stuck. Removed both the cap and plastic housing on both sides and after cleaning it, put some lithium grease and got it loose again. Now the problem is that the idle is not working fine. Sometimes it cold starts too low, sometimes is fine, same thing when engine is hot. IAC valves have their lifetime and mine already has 200,000 miles on it (have cleaned it for the third time). Can get a new one for $75 at rockauto.com.

Hope this helps :)
 
Mine's started doing this as well. Thought it was just the colder weather but now I have doubts. I understand the 1,000RPM idle when it's cold but it does it after warmed up sometimes. If I just pop the throttle a bit it comes back down to 650-700. Same issue? Might be time to clean my throttle body again.
 
Gerdo said:
I have checked all vac lines, everything looks good.

I'm thinking IAC.
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Sounds like a sticky IAC. I'm guessing you can't blip the throttle like Jon can to bring it down?

SantaCruzRunner said:
timing belt?
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No.

Jon said:
Mine's started doing this as well. Thought it was just the colder weather but now I have doubts. I understand the 1,000RPM idle when it's cold but it does it after warmed up sometimes. If I just pop the throttle a bit it comes back down to 650-700. Same issue? Might be time to clean my throttle body again.
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Sounds like your throttle body is dirty, lube the throttle return spring, too. If you plan on pulling the throttle body to clean you should pop the IAC and make sure it moves freely.
 
most likely not it, but. If you messed with the cruise cable at all lately make sure you have it back in the right orientation. It prefers to sit a convex angle if your looking at it from the front. If you pick it up and push it over to another angle it likes to settle (concave to you know from the front) it kicks your idle up to right about what your desrcibing.

Was that coherent? You guys get what I'm saying? I had a hard time describing this. It Happened to me once, probably not your issue but thought I would share.
 
I have removed the cruise cable, no change.
I have removed the IAC, cleaned it and tested it. It seems to check out but it didn't look like it closes all the way. I have a new one on it's way. I'll see next week when I install it.
 
CharliePR74 said:
Check your IAC Valve. Happened to me weeks ago when finished replacing both head gaskets. Put everything back again and at cold start, idle was too low and then as soon it was getting hot, idle started to get higher till 1100 rpms. Opened and checked it and found it was stuck. Removed both the cap and plastic housing on both sides and after cleaning it, put some lithium grease and got it loose again. Now the problem is that the idle is not working fine. Sometimes it cold starts too low, sometimes is fine, same thing when engine is hot. IAC valves have their lifetime and mine already has 200,000 miles on it (have cleaned it for the third time). Can get a new one for $75 at rockauto.com.

Hope this helps :)
Click to expand...

Mine behaves better now but pretty sure at least in my case is the IAC. Sometimes the engine just doesn't start but if I press the pedal a little bit, then it just goes. One of the signals IAC's show when they're getting stuck.
 
A co-worker told me to check the throttle body, get it cleaned cause sometimes it gets stuck as well due to the fuel and dust residue that sticks to them. I'll check mine this weekend.
 
Last weekend I cleaned my mass air flow sensor (with electronic contact cleaner). It was super dirty and black. Then I used carb medic to clean the butterfly valve in the throttle body.

Mine actually idled higher (~1000) after I did the maintenance. I don't really mind it, because it's cold enough here I need it.

I think it could be normal. Does anyone know what a brand new 3rd Gen idled at in park?

Edit: I also changed my PCV valve.
 
Last edited:
I just got mine and when I fire it up it revs at 1500rpm! I guess I'll clean the suggested parts and see if it gets better
 
The engine revving as high as 1500 rpm when the engine is started cold, especially at colder ambient temperatures, is normal. If the idle rpm drops to around 700-800 rpm when the engine is at operating temperature, you likely don't have a problem.
 
Okay so when you cleaned the IAC you probably sprayed the TB with carb cleaner. The liquid dissolves the carbon that had built up and drained down the holes in front of the butterfly valve. The carbon then dries on the pintle valve of the IAC lodging it open so that it stays in the cold engine mode ( ie high idle). So what to do? I had the same issue. Here's what worked for me. The engine has a fair amount of suction through the IAC and what you want to do is help it suck the carbon past the valve. Once it cleans itself, it will return to normal function. Go buy a can of MAF cleaner. It's more expensive but its less aggressive than carb cleaner and won't leave any residue. While the engine is stone cold, remove the plastic intake tube to the throttle body and push it aside. That will expose the throttle plate. Squirt 3 shots of MAF cleaner in the hole in front of the throttle plate. Then quickly start the engine. It will fire up and then stall out because the MAF is not reading any air movement. That's exactly what you want it to do. There's no harm so don't worry. Repeat this 3-4 more times. This will dissolve the carbon and then suck it past the valve. There's no reason to replace the IAC or remove it. It wants to work but can't. This will free it up to start moving again.

Then reinstall the intake tube and make sure everything is connected and try starting the engine. It should fire up and idle down as it warms.
 
All caffeinated up

Drcoffee said:
Okay so when you cleaned the IAC you probably sprayed the TB with carb cleaner. The liquid dissolves the carbon that had built up and drained down the holes in front of the butterfly valve. The carbon then dries on the pintle valve of the IAC lodging it open so that it stays in the cold engine mode ( ie high idle). So what to do? I had the same issue. Here's what worked for me. The engine has a fair amount of suction through the IAC and what you want to do is help it suck the carbon past the valve. Once it cleans itself, it will return to normal function. Go buy a can of MAF cleaner. It's more expensive but its less aggressive than carb cleaner and won't leave any residue. While the engine is stone cold, remove the plastic intake tube to the throttle body and push it aside. That will expose the throttle plate. Squirt 3 shots of MAF cleaner in the hole in front of the throttle plate. Then quickly start the engine. It will fire up and then stall out because the MAF is not reading any air movement. That's exactly what you want it to do. There's no harm so don't worry. Repeat this 3-4 more times. This will dissolve the carbon and then suck it past the valve. There's no reason to replace the IAC or remove it. It wants to work but can't. This will free it up to start moving again.

Then reinstall the intake tube and make sure everything is connected and try starting the engine. It should fire up and idle down as it warms.
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Dr coffee rocks. I had this exact issue and this did the trick

I had just pulled the whole engine bay apart replacing plugs and valve cover gaskets, and had of course cleaned the heck out of the intake while I was at it. Put it back together and it ran like a top, but was idling at 1500. Did a little googling and found this post. I just used carb cleaner and had to run through the described process twice, but cleaned it right up. Purring at 700, thanks for posting.
 
Dr coffee, you are the man!!! This high idle had me on the brink of a nervous break down. I did this little trick and she is running like a top. Thank you sir!
 
High Idle & Rough Low Idle when warmer

Hello DrCoffee and all,

Thank you for adding to this thread. I just replaced my valve cover gaskets and spark plus on a 2001 4Runner and besides leaking oil, it was running fine. Now, after completing the repairs, the engine is running rough at low idle and if it stablizes and becomes smooth, it's idling at 1300-1500 RPM. I ready DrCoffee's comments, but I can't recall where the hole in throttle body plates is. Is the throttle body plate the same as the big tilting valve inside the throttle body or are you referring to something else.

I would take the IAC valve off and check, but as someone mentioned, with a 2001, I can't do that. I did spray carb cleaner in those vacuum ports entering and exiting the IAC, so that might have loosened something up.

Please send your comments.

Thanks,

Mathew
 
Did not work for me. Threw one CEL. Idle sat at 1100, but then went back up to 1800 after engine was warm. In drive, she sits at 1100....anyone else have this issue?
 
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