Idle issues

[cb_240]

Rb25 in an s13

car is running fine, the idle is at about 1200-2200 (it varies from time to time after i turn the car off and restart it) I've got a q45 throttle body on it on a greedy style intake and i've adjusted the screw on the throttle body out and i've played with the screw on the aac valve (now all the way in) and this is as far as i've gotten

What is really giving me a headache tho is when the car idles (stopped at a red light, or just sitting after start up, etc.) the car fluctuates between 1200-1800 rpm constantly

like it goes up to 1800 then drops off and up and down etc. and just keeps doing it. If i rev it it stops for maybe 3-5 seconds then will start doing it again, i'm just wondering what is causing this and where i should look to solutions.

I read somewheres about needing an aftermarket fuel pressure regulator to compensate for the walbro fuel pump?

please help, I got a taste for the RB and I want more

[cb_240]

anything guys?

might have fixed the fluctuating idle, but the car starts idling higher and higher the longer i have it running, for example today when i pulled it out of the garage it was at around 1200 when i stopped it from fluctuating, drove 5-10 mins and the idle was at 2400 so i adjusted the aac valve in and it brought it back down. I had the car sitting all day and started it up and the idle is still at 2400 so i again adjusted the aac valve all the way down and nothing.

any insight?

when driving in 5th gear the car was able to pull me at 80kms without even touching the gas

[mello88]

Start with the easy stuff, do a boost/vac leak check to make sure there are no leaks after the TB. The fluctuating idle sounds like something with the AAC, maybe it's gunked up inside, have you tried cleaning it out? You could also watch the voltage the ECU is sending it to see if it matches with the fluctuation... GL

[craz4240]

Yeah Kyle check for leaks,set your idle switch.

[meet07]

I noticed the same thing yesterday. Popped the hood and presses the TB lever in and it idle fine. I was thinkin that the linkage on the tb might of needed some greasing.