Sorry if this has been discused before. I thought I remember reading someone asking about this but I cannot find the thread.

I've noticed the idle jumps around on my 2012 Evo. Jumps above 1k and then below 1k when in nuetral or when my foot is on the clutch. I bought the car new and it has pretty much done this since I bought it. The car is stock also. Is the idle fluctuating normal?

 

There is a sticky it's the Fuel pressure Regator hose. Its and easy fix you just need a zip tie

 

The slight fluctuation is normal on the Xs. If it fluctuates badly and above 1k rpm at idle, you might have something else that is wrong...such as the FPR hose.

 

mine does that too sometimes, but its usually close to 1K when I start the car and in couple seconds it idles normally.

 

does it do this when the engine is warmed up or cold?

 

When its warmed up and I have been driving around.

When I first start it up it will be above 1k. Maybe around 1.3k or so. It holds idle there while I sit and let it warm up for a few minutes. Usually it will then be around 1k after sitting a few minutes and thats when I start driving to my destination.

As Im driving it will usually be around .8k if I am not giving it any gas. For example if I approach a stop sign I would throw it into nuetral. Usually it will be about .7-.8k. But sometimes it bounces and fluctuates a bit. In nuetral with my foot off the clutch or if coasting with my foot on the clutch is sometimes fluctuates to above 1k. Maybe about 1.1k. And then bounces low to close to .5k-.6k.

Its pretty much done this since I bought it. Im just wondering if the idle fluctuation is normal for these cars(stock)? Should it hold .8k pretty steady when in nuetral? Or does other people's Evo fluctuate the rpm's a little when in nuetral or clutch down?

If its normal I wont think nothing of it then. Sounds kind of cool though when it does it. The exhaust makes it sound like it has a rocking cam of something.

 

I believe it has to do with the "drive-by-wire" throttle system, or what ever its called. It's not a "normal" throttle, or what is in most cars. To have it fluctuating like that is pretty normal. Especially for a stock X..

 

My IX does the same thing. Sometime when I am stopped at a light the idle will rise up to 1k hold there then drop. I did some research and narrowed the symptoms down to a dirty MAF but when I took the intake apart to check the MAF, it was clean. It sill happends and i've no clue on what to trouble shoot next.

 

you said car is warmed up. warmed up to operating temperature? If you been driving for while and idle fluctuate listen for the fan. If the fan kicks on the idle will fluctuate due to more load.

 

For me I dont think it will be a dirty maf....my car has 400 miles on it

 

wow i noticed that too on my brand new GSR 2012 i have like 500 miles and the start up idle sometimes it bounce up and down too ..... sounds weird and not smooth ...

 

my 2010 X has idle problem too. when i turn the steering wheel at idle, there is always a clunking sound and can feel some vibration. but when it idles going in a straight line or turn the wheel at a slightly higher speed, there is no problems at all. do you guys have the same issue? what exactly is causing this? should i go to the dealder and have it checked? thanks in advance.

 

My 2008 would do the idle jump as if the car was running on Mexican jumping beans but after my AEM intake and DW65 fuel pump install the car has yet to repeat it.

 

Had this issue also, discovered it was the aftermarket bov I had. switched it up and the problem was gone.

 

Mine stays below 1k but moves around a little when sitting at a light. I can see a RPM difference when the clutch is in or out but I don't recall it ever going over 1k once warmed up. I am going to check it out tonight on my way home.