96 Avenger idle speed
 

It started when idle speed suddenly rised to 1700Rpm.
I suspected the idle air control valve, so I took off the throttle body, battery disconnected.
It was very dirty so I cleaned it and replaced the idle air control valve with a new OEM Mopar with part#4796503AB, and a new throttle body gasket.
Connected battery and started, idle now 2300Rpm.
I connected OBDII scan tool, no faulty codes to be read.
There is also no light in the yellow engine light in cluster.
So still running with 2300 RPM.
Any suggestions?

Thank you.

Vacuum leak

Checked all vacuum hoses, all OK,
Found the PCV valve to be leaking a little bit, and the EGR transducer solenoid did not hold vacuum when engine running. Plugged both lines, but still the same; 2300rpm.
When engine is at normal temperature and I give full throttle and release it is like the engine will go down to normal idle but just before it comes down to normal its like it gets a signal and then idles instantly back to 2300rpm.

Today I checked the throttle position sensor and it is OK.
I plugged the throttle body air inlet but still running at 2300Rpm.
So I suspect the EGR system. Unplugged the vacuum hose on the EGR valve and it was sucking air.
Will do some further testing of that system and see.
Plan to just plug the line on the air inlet manifold.

Done a bit more testing.
I put a vacuum pump on the EGR valve to see if it was working, and it opens and close (still might leak thru). Connected the pump on the hose to the EGR valve and started the engine. Still running at 2300Rpm. I applied vacuum to the valve and the RPM drops to around 1000. Still not OK, but I am going to change the EGR valve with a new one.

IIRC you need a scan tool to get the pintle on the IAC to move to the appropriate position.
I went through about 4 new IACs before I pulled one from a junkyard, problem solved.

I am not sure what you mean.
To replace the EGR need no programming as far as I know?

I have never had a bad EGR cause an idle issue, so I'm not sure why you're even looking at that
Your Idle Air Control Motor (IAC) controls engine idle. You stated it was idling at 1700. Then after cleaning the throttle body and replacing the IAC, it now idles at 2300. This tells me either your IAC is faulty, or it's extended/retracted farther than your ECU can make it move, which will take a good scan tool to get it to move to the proper position.

Well, the EGR is leaking so it will have the same effect as a vacuum leak. Even I plug the throttle body inlet it still gets enough air to run at 2300Rpm. Normally it should choke and stop the engine if the throttle body inlet is plugged. So that is why I would replace the EGR.


Back to the IAC that you mentioned, now I will try to clean my old IAC and put it back to see if that has an effect on the idle RPM. Thank you for the info on that.

I have now cleaned and checked the old IAC, then reinstalled it, but still the same (2300Rpm).

Why is it that once I disconnect the EGR and put vacuum directly to the solenoid valve it drops to 1000 rpm, but not running smooth?