I have a high idle and idle surge issue. Ive cleaned the iacv and replaced coolant temp sensor still no change. Have checked all the vacumm hoses for leaks and they seem to be good. Not sure what is going on but its driving me nuts

 

What engine? Stock? Modified?

CEL codes?

 

Stock engine d16 non vtec. Code was for o2 sensor. I unplugged the map sesnor idle came down a couple hundred rpm but was boggy when accelerating

 

D16Y7? Be specific.

Was or is? When was the last time you checked for codes? What are the specific codes?

 

A ton of different things can cause a high idle. The most common being a vacuum leak, throttle body issue, or the IAC. If the coolant temp sensor was bad the car will generally idle fine after it has warmed up. For Vacuum leaks there are other things other than the vacuum lines that can leak such as the intake itself.

Did you have codes or did a scan tool indicate the coolant temp sensor was reading faulty?

This will need to be diagnosed properly as so many different things can contribute to the high idle.

This article explains well causes of a high idle. https://www.yourmechanic.com/services/engine-idle-speed-is-high-inspection

 

Good bet is on Idle Air Control Valve if you checked vacuum lines are all connected and sprayed starting fluid along them with no effect

If you cleaned the IACV before this started or got worse, you may have actually dried out the bearings in it and froze it like I did to mine

You can pick one up new on Ebay for real cheap- just always look for a seller with lots of positive reviews!

(I got an OE one new on Ebay from China for $30 which fixed mine bouncing 3k to 1.5k rpm nonstop in park/N but running totally fine in gear)

my $.02

also, if you pulled the throttle-body to clean it or or the IACV, make sure you get an OEM TB gasket for it if you didn't at the time

 

I cleaned iacv no change went and got one from junkyard still no change... As for the codes i will scan tomrrow and post them up

 

Required info^

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Also, do this test:

Remove air intake.

Use finger to cover hole inside TB leading to IACV.

Does this stoop the high surging idle?

 

That killed the motor. I fixed the issue i actually took the time to figure out how the iacv works and realized the valve was stuck freed it up and she runs great now