I searched and found nothing related to my problem. I had this wacky idle problem since I bought the car. I did get the factory reflash which took care of it for about a year. All of a sudden a few days ago, once the car is warmed up the idle jumps from 400-800 at every stop.I always try to blip the throttle to stop it but it just keeps doing it. Well today I just tapped the throttle while it was hesitating and my revs went to about 4k and just stuck for a second and slowly, I mean slowly dropped back down to its normal erradic idle. Took about 10 seconds for it to drop back down. Any ideas as to what would start causing this? By the way my car is bone stock with the factory reflash.

 

Treat her bad. Push her to the top, these cars are kind of sadomasochist. They like hot and rough.
After a month provably everything broke or fixes.
Mine work like a gem on 115 degrees burning days
In winter she goes faster but the trans. feels like an old lady.

 

Dude, are you sure the fuel pressure line didn't pop off?

Looking in your engine bay, it's on the front left of the engine. No need to remove anything to see it.

 

Definitely check the FPR. The next thing after that is to check for codes. It should not do that at every stop.

 

yep! I guess i shoulda checked that first. I assumed that wouldn't be it cuz I wasn't driving it hard at all lately. There is no clip on that line so I put a tie strap on it for now. Thanks to everyone for the info.

 

would that explain why i got a random lean code the other day?

 

had a recall on that a while ago. You should take it to the dealer and have them fix that.

 

Yes, definitely.

 

I am experiencing similar issues with my evo X. Just a rougher idle when I am stopped at a light. I don't have any different tune than what came from the factory. From reading other the responses I checked out what i think is the fuel pressure line and everything seems in order. I think it looks like a two smaller rubber hoses connected by a larger rubber hose without any fasteners or clips. Could anyone take a picture of what exactly the FPR is and what exactly it should look like correctly. Thanks guys!

 

look in this thread
https://www.evolutionm.net/forums/ev...d-my-idle.html

 

Mine is as you described, seems like a hose wrapped in a hose. I couldn't budge the hose, I can't imagine it just falling off on its own. Maybe it is temp related.

 

Wow, easy fix! thanks for guiding me in the right direction. I just hope I didn't put the zip ties on too tight lol!

 

I have the idle issue and have had a couple recent "system lean" codes tossed. I'm pretty sure they're related to the rev issue not slowing down. I did that in front of a car guy, racing dude, and he says "too lean" that he could even hear. My TBE is the cause for normal idle and the other "lean" I'm pretty sure was a dirty air filter. Make sure it's clean. I keep checking to see if the FPR hose has fallen off, but it's still hanging in there.

 

BTW, when it's not bothering you and you're checking the fuel economy, what is it if you drive it like grandma? If its over 22, you have a lean(er than stock) running car.

 

I think Im in the same boat. It just started doing it today, it'll start perfect and about after 2-3 mins of it just at idle it'll drop from 1k rpm to about 500 and sounds like it's going to stall but then it revs up to around 2k and back down then repetes itself bouncing idle then rev up. I was told the TB could be cleaned, then I was told it could be MAF issues. Have a appointment at the Mitsubishi dealer but would rather figure it out on my own and save myself some money. Anyone have any answers to these issues? Forums seem to have slim answers..