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fourty4magjr 04-22-2013 08:59 PM

Idle help
Ok so for about 5 days now my jeep would idle rough it would dip a little bellow normal idle. Tonight I got back to the house and decided to leave again a few min later. Got in the jeep started it and while I was getting situated it started to idle rough for the first time in a day or two. I reved it to 2000 with a quick push of the gas like I did the other times it would do this (seemed to stop the rough idle) except for this time te idle dropped all the way to the 150 ish. Shut the jeep off and started it back up and no problem every thing was normal. Drove it stopped at the first light seemed ok. Second light it did it again! Then didn't do it until my way back home but only did it twice. This whole time the jeep never had a chance to cool down so it was warmed up (~210). Oh it also felt like it had a ton of torque after te idle would drop and I woud hit the gas almost felt like it wanted to drive itself(if that makes sense). Lights seemed to dim a bit when this happened as well. Any clues? I've searched rough idle when this first started happening but nothing seemed to be the same as mine. :confused:

fourty4magjr 04-22-2013 10:19 PM

I'm going to clean the iac tomorrow and hope it helps. Any input guys/ girls?

fourty4magjr 04-23-2013 09:25 AM

Bump for any help!

fourty4magjr 04-23-2013 11:19 AM

Guess I'm on my own with this one. Oh well hasn't done it yet today when I went to go get carb cleaner so maybe it's just a random thing.

DarrenT 04-23-2013 11:56 AM

I would have said IAC, but you nailed that already. :thumb:

mrbat23 04-23-2013 12:28 PM

I had a similar problem, and also could not find a answer in the search forum.I ended up replacing iac and tps which helped slightly, but i decided to change all 4 of my o2 sensors( I know over kill , since i believe the upstream sensor can affect idle).to this day it has purred like a kitten.

fourty4magjr 04-23-2013 01:23 PM

Yeah o2 sensor is my next guess because I just cleaned the iac but didn't help. So I drove to get the carb cleaner and nothing happened then drove to get gas still nothing it was completely normal. Then I get home and clean the iac and decided to do the throttle body as well. Cranked it up and started and was fine. I revved it a bit so I could spray te cleaner on the throttle body to get the rest of the crap off of it and reved the motor so it wouldn't die on me and when I was done it started to instantly idle rough... So I'm guessing either the iac is bad or I have a bad o2. Now that I think of it yesterday I reved the jeep up pretty high when I was getting onto the highway (it's good to get the motor up in rpms every once and a while) and that's when it started this severe low rough idle crap and did it again after running fine all day just after I reved it up. Could that lead to a diagnosis or am I just putting random garbage together and thinking to hard?

DarrenT 04-23-2013 01:39 PM

Doesn't an O2 problem throw out a CEL and ECU code?
I had an O2 problem when I first got mine (post cat sensor) and that came with a CEL and ECU code. In fact there wasn't a problem as such, there just wasn't a sensor left....
From monitoring the data from the O2 (torque pro) I could see how a pre-cat O2 failure could cause this, but have never experienced it on a post cat O2 problem, and would have expected a CEL with either one.
Again I've had rough idle due to knackered ignition leads, but that threw out the old misfire code. I'd be tempted to plug it in and read the data, whether there's a CEL present or not.

flflash 04-23-2013 01:53 PM

Just becuase you mentioned dim lights and problems at low engine speed it might be a good idea to test your batteries state of charge and your charging system. Low voltage in the system can cause all sorts of driveability issues on computer controlled vehicles.

fourty4magjr 04-23-2013 02:16 PM

You know the battery thing seems like it could be it. This has been happening since I put an amp and sub woofer in. I accidentally drained the battery the first day having it by running it to long without starting the jeep so maybe it is a charging issue because the amp is drawing to much power? And I'm planning on running for some codes in the next day or two If I can't figure it out.

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