This has been happening the past few weeks. I go out in the morning and start her up and I get a rough idle for a few seconds to a minute. After that its fine. Its not very rough but it is enough to notice. Did the plugs, cleaned the injectors and throttle body. What could be causing this? :wave:
Rough idle on cold/first startup of the morning.
abnormal
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This has been happening the past few weeks. I go out in the morning and start her up and I get a rough idle for a few seconds to a minute. After that its fine. Its not very rough but it is enough to notice. Did the plugs, cleaned the injectors and throttle body. What could be causing this? :wave:
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5,995 Posts
I am still looking for some ideas on what is causing this rough idle.
Also While I am at it I entered STAGE 2 by adding black steel wheels to the Jeep. Now I am going to order my bl and mml soon then the 33 12.50 trxus MT's are going on. Then to complete STAGE 2 I just need to get my lift ordered and put on! Then on to STAGE 3 where I tackle the lockers, winch, bumpers, and pretty much anything else I haven't put on! :thumbsup:
Also While I am at it I entered STAGE 2 by adding black steel wheels to the Jeep. Now I am going to order my bl and mml soon then the 33 12.50 trxus MT's are going on. Then to complete STAGE 2 I just need to get my lift ordered and put on! Then on to STAGE 3 where I tackle the lockers, winch, bumpers, and pretty much anything else I haven't put on! :thumbsup:
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1,043 Posts
try cleaning the TPS + connector (+IAC) ...
What plugs did you use? Mine ran really rough for 5-10 seconds when starting up cold. I changed plugs (Autolite Platinums) and it still did it, so I just figured it was the nature of the beast (I had also ran fuel system cleaner and cleaned all parts of the throttle body). I recently changed plugs again to the Champion Truck Plug 4412 and now it starts and idles as smooth as can be. Many people on here will claim that the Jeeps with distributorless ignition do not like platinum plugs.
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160 Posts
I have had this exact same issue since last July. I have replaced just about every sensor under the hood. i have many posts on this very same topic with no solutions yet. My latest trip to the dealer told me that the truck plugs are one heat range too cold for the engine. So I put in the factory plugs and it runs worse than before. If it is the plugs then I'm thinking you just have to find the right combination. I never got an error code with my idle problems. it seems to clear up after a few moments ( once the oil pressure gets up ). Wish i could be off more help but I will let you know any breakthroughs I might have.
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936 Posts
Sounds like your IAC is dirty or is going bad. I removed mine and cleaned it a while back with choke cleaner. It worked ok for a few more weeks then went back to rough starts. The IAC or Idle Air Controler is basically a motor with a finger that goes in and out of the throttle body to allow more or less air to flow. At Startup, or when you turn on your AC it puts added load on your engine, the IAC increases airflow to accomodate. My IAC wasn't throwing up an engine code, yet now that I've replaced it with a new unit, the Jeep runs Much better.
PS - My rig only has 20,000 miles on it, but I take it off-road nearly every weekend which may have caused my IAC to wear out early.
PS - My rig only has 20,000 miles on it, but I take it off-road nearly every weekend which may have caused my IAC to wear out early.
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2,427 Posts
reminds me of an muscle car, especially with the flowmaster. Now if it would only run like a muscle car
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1,590 Posts
Mine too, I started in on it like everyone else, replaced the front O2 sensors, spark plugs, and cleaned the IAC. I was going to keep at it, until I decided it was such a minor issue I would cut my losses and forget about it. I just let it warm up for 10 seconds and it's good, supposed to do that anyway.
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