Hanging/irratic idle - searched, remedy not found

[Amani77]

Quote: Originally Posted by bigblockcoupe

I actually had one of those wires break on the plug to the tip but that threw a code... R u throwing any CEL's?

Im not throwing any codes, relative to tps, iac, or tip =(

[bigblockcoupe]

U might've covered this earlier and I apologize if u did but r u on PCM controlled boost?

[BoostinBen]

No PCM controlled boost...AVC-R controlled boost. Car boosts perfectly, pulls perfectly, etc. Haven't had a change to take it out again but may today for a bit. May remove the TIP line and just block off the port entirely at the sensor itself so it's not seeing any sort of atmospheric change and see what happens.

[SRTFerg]

I am having the exact same problem. The car drives itself at times and idles high before coming to a stop. I might have to try to unplug my TPS

[LinkLow]

I was recently having this problem also...I tried replacing both sensors (TP and IAC), went through all wiring, etc. What worked for me was forcing the throttle plate shut by the spring/throttle plate where the throttle cable bracket connects to the TB. I did this with the car was running and the problem was happening (just be careful, the radiator fans can come on at any time the ignition is in the "on" position) For some reason, the throttle plate was hanging open just a hair, even though the cable had a little slack in it.

[BoostinBen]

Quote: Originally Posted by LinkLow

I was recently having this problem also...I tried replacing both sensors (TP and IAC), went through all wiring, etc. What worked for me was forcing the throttle plate shut by the spring/throttle plate where the throttle cable bracket connects to the TB. I did this with the car was running and the problem was happening (just be careful, the radiator fans can come on at any time the ignition is in the "on" position) For some reason, the throttle plate was hanging open just a hair, even though the cable had a little slack in it.

What do you mean "forcing the throttle plate shut by the spring/throttle plate"?

Do you mean taking your hand and applying force where the throttle cable attaches to the throttle body to close is entirely or what?

[srt4srsexy]

had same problem checked all that stuff ended up being bad crimp at tip wires the wire was moving in and out of connector.when you start your car look at a/f gauge and see if its pretty studie or if its all over the place thats what led me to a wiring problem.hope this helps.

[BoostinBen]

Quote: Originally Posted by srt4srsexy

had same problem checked all that stuff ended up being bad crimp at tip wires the wire was moving in and out of connector.when you start your car look at a/f gauge and see if its pretty studie or if its all over the place thats what led me to a wiring problem.hope this helps.

Yeah thanks for the input. A/F at idle stays right around 14.6/14.9 respectively. No fluctuations but I am thinking it's also time to replace the wideband O2 sensor...

[BoostinBen]

I took the car out today and the problem didn't really occur. It happened initially on startup and pulling out of the parking deck, but around town I only had maybe a few instances of the RPMs not dropping until coming to a complete stop. I'm probably going to remove the throttle body here in the next week or so and see if it's closing entirely or what's going on.

[19 psi]

sounds exactly like tps issue also worn pcv valve can cause high rpms right around 3000but if you take off the stock pcv valve youll have to replace it due to the screw on design so just blow and suck it to make sure its not stuck. my grandma lives in shaker hights

[BoostinBen]

Quote: Originally Posted by 19 psi

sounds exactly like tps issue also worn pcv valve can cause high rpms right around 3000but if you take off the stock pcv valve youll have to replace it due to the screw on design so just blow and suck it to make sure its not stuck. my grandma lives in shaker hights

I was thinking of replacing the PCV valve. Hmmm.

The idle is much better since the sensor was replaced. Still plenty of slack in the wires, too, so the re-wire I did a year or so ago looks good. No broken ends or anything.

Cool about Shaker Heights. I'll be here only a few more months longer then it's down south for me

[Garmz]

Solution: 1 Can of Brake Cleaner. Spray liberally over intake manifold gasket.

[jester-]

I had the same issues as you described here. After pulling everything apart, I had a severed wire in the IAC AND the TPS.

Here is how it would idle:

YouTube - Idle Issue Dodge Neon SRT-4

YouTube - Idle Issue Dodge Neon SRT-4

Also had hanging RPM's both in and out of gear. Idle would sit at ~1500 RPM after I started driving and would calm down to whats seen in the video if I sat in one spot for long enough. Unless you checked both the TPS wire and the IAC wire all the way to the PCM I'd go back and pull the engine harness apart and inspect them both. I didn't see the IAC wire at first and only noticed it was borked when I went to reinstall the fixed TPS wiring.

Also, when my intake manifold gasket was missing a large chunk out of it, the only symptom it caused was a high idle (and loud whistling).

[BoostinBen]

Quote: Originally Posted by Garmz

Solution: 1 Can of Brake Cleaner. Spray liberally over intake manifold gasket.

This is not the solution. I do not have any intake manifold leaks and replaced the gasket maybe 2k miles ago.

In other news, clearly my solder job on the re-wire was crap because when I pulled the tape back I could see the black wire had disconnected where I soldered. I re-soldered it, and things seem to be much better now.

As far as the IAC is concerned - I have the AGP screw-in unit and I periodically throw a code for it so I will have to check those wires, too.

[MOPARfulSRT4]

BUMP! I have the same issue. I read on the forums that it might be due to a bad air intake filter. I bought a new filter for my AEM intake and at first the problem continued but after a few minutes of driving the problem went away for a couple days. Now the problem has come back. Has anyone found a solution? By the way, I replaced my intake manifold gasket a few months ago along with my TPS when I first had the issue. Problem went away for a few months but has returned now.