I just purchase an evo im having problems with the idle it start to shake alot when i got the a/c running and the car is at a stop it almost feels like it want to shut off put it stay at 900 to 1000 rpms feels like a misfire but when its driving it running perfect. So far what it has done is a recirculating bov by forge with injen piping, has a dump tube full down pipe exhaust boosting at 20 to 21 psi i was able to to lower the idle abit because when i purchase it it was idling at 1300 rpm. I also bought new spark plugs. If anybody has a suggestion please help thank you.

 

I would check for a possible boost leak. Could also be tune related.

 

It sounds like you need to have it tuned. Mods in my sig and my car idles fine with AC on/off.

 

Or like viegas said, check for leaks.

 

So does it idle OK when the AC is off?....how about AC on while idling at 1300 rpm, was it ok then?

 

When the a/c is off it idles fine I think it sounds like it has a cam not to aggressive. But after a good while drive is starts a bit but not to bad

 

What could it be.

 

did you check the iac? idle air control

 

id say its the tune as well

 

i don't think a boost leak would run well when driving unless you weren't in boost

 

It pulls fine just the idle has its weirdness I will be checking the iac and doing a boost leak test soon.
Just to make sure the iac its on the throttle body but underneath it so I would have to take the throttle body out right.

 

I had similar problems and it was my iac! Question, do you have to keep your foot on the throttle for cold starts? and when warmed up it runs fine? yes it's on the tb and you don't have to remove it. When I did mine I removed the battery and upper I/c pipe, there's three small phillips screws holding it in place, one's a little difficult to get to, just don't lose them, and make sure the o ring is in place and sealing. Just make sure that it is what's malfunctioning first, because they run $300+ @ the dealer,or you can get them used on this forum in the classified or ebay for around $60-100+. part #1450A069 - IDLE SPEED CONTROL