420A Rolling idle surge

[JakeGS]

What's up guys.

I've searched and searched and I've found some useful information but a lot of stuff I have found deals with parts that I don't think my car even has

But my car is the 420a Eclipse GS and my car has an idle surge but it mostly happens when I push clutch in, ittle jump about 500rpms or so.
Some things I found that I don't think I have are:
Idle speed control
base idle speed screw
The two things that I know I have and have either replaced or checked is the
Idle air control
throttle position sensor


I haven't done a vacuum test but I've listened to the hoses as it was running for a whistling noise

 

[Andrewl 91 1g]

I'm having almost this exact same problem. My idle surges rolling but as soon as I stop it steady's out to normal. I've changed my idle air control too.

 

[fisher83]

Does it make a difference in weather the motor is cold or at operating temperature? Do you have any C.E.L's? Check vacume hoses, check injector seals( spray a little starting fluid around them and listen for a change in idle) check the engine coolant temperature sensor ( its the bigger one on the thermostat housing) check all your evap hoses. Theres the one from the egr solenoid to the intake manifold, theres another one from the manifold that runs down to the passenger side that turns Into a hard line that leads to the evap canister in the passenger front corner under the headlight(I think thats what that canister is called).

 

[Andrewl 91 1g]

For mine it doesn't matter whether it's cold or hot and it doesn't matter how much I'm rolling. Any roll at all with the clutch in or in neutral it surges from about 1k to 1200-1300.

Yes I have a CEL but I don't have a OBD1 reader and neither do either of the autoparts stores close by.

2nd edit: Also my oil pressure drops quite a bit at idle it's the stock gauge so I don't know how reliable it is.

 

[JakeGS]

Sorry I haven't been able to awnser back because I'm still trying to get stuff together to transfer colleges, but any who, I've been checking around the car when I have had time, the few vacuum hoses I've seen look to be alright, I've gone ahead and replaced spark plugs/ wires just to be safe, I tested one of my O2 sensors went bad so I went ahead and took it out and decided to move my car to a flat surface so I can jack it up and test the other one, we'll for some reason with the O2 sensor out it idled just fine it didn't stick at all so without changing the second o2 sensor I took another car up to advanced and bought a replace ment, we'll for some reason with the new o2 sensor in it idles the same as before but if I still tAke it out it idles how it should any ideas from that extra information?

 

[JakeGS]

Just went out side to try the starting fluid and it idled normally the whole time
And I believe my temp sensor works because a few days ago I started to over heat since one of my hoses wasn't tight enough and I was getting air bubbles in the coolant

 

[JakeGS]

I finally got a check engine light from it and doing a self diagnosis (turning key of and on 3 times) I got code 25 Haynes manual says "iac motor circuits. A shorted condition is detected in one or more of the iac motor circuits " which could be one of 2 things either I got a defective iac motor or 2 I have something wrong with the wiring harness but would I pull this code if it was the wiring harness?

 

[fisher83]

It would probably send a code because the pcm isnt getting the correct signal back. If you have a chiltons manual it will tell you the voltage you need to the iac. There is 4 wires on the harness, it will take you through the whole procedure.