idle problem

[caRalliArt]

I took my evoX fmic off and replaced it with the stock one.Now the car doent idle very well.It tries to die.The rpms bounce between 500 and 1000.What is causing this? I checked the intercooler and pipes.They all seem to be on and tight. Is this a vacume leak?

[wwralliart77]

Make sure the line to the fuel pressure regulator didn't come off; that causes the afr to lean out and could cause your engine to stall and potentially blow. If you're tuned, were you tuned with the larger ic? If so that could pose a potential problem, since you were programed to receive a larger amount of air.

[caRalliArt]

It drives fine.But it doesnt idle.If the fpr line came off wouldnt it run like crapp?

[highcaliber]

Mine would do that from time to time after a long (2+hr) drive. After I got my evo x I/C, BOV etc installed and had it tuned, it stopped and hasn't had a problem since. The MAF sensor in the RA is stupidly sensitive, to the point where even changing from the factory airbox causes the check engine light to come on. (I'm sure you knew that already so I'm not intending to lecture here) so I wonder if changing from the larger (and likely less restrictive) evo I/C to the smaller stock I/C with smaller piping might cause it to freak out?

Did you have a tune when you had the evo I/C in? If you did, and you went back to stock, you might need to have the car re-tuned to stock.

or I might be full of hot air...

[KrazyRA]

I would say change the tune back to stock with stock pill. or your MAF sensor went bad. That sounds like how mine was and they replaced the MAF sensor went back to normal.

[wwralliart77]

So you removed all your mods and went back to stock since you were/are planning on selling your RA? You are now having some idle issues since you swapped out your ic.

If you were tuned for certain mods that are no longer installed, the vehicle still thinks they are there and tries to compensate. Which is the most likely cause of your idle issues. +1 on reloading your stock map being your best bet.

[MTZL]

Evo X GSR & MR has the same idle issues.
I think it has to do with fast acceleration & deceleration.
Every performance car has idle problem after fast acceleration & deceleration.

I put it Neutral anytime I come to full stop. Idle better than in 1st gear.
I remember seeing idle stabilizer or some sort. I need to further educate myself before I mislead yal.

[caRalliArt]

It never had this idle problem before.I flashed back to the gst 91 base flash.still have problem.any ideas?

[MTZL]

Maybe vacuum line?

Pic of your engine bay?
List of mods?

Does the problem still exist putting it in neutral?

[caRalliArt]

Genius.I looked really hard at all the vacume lines and found the fuel pressure regulators vc line was unplugged.good tip.thanks