idle up and down up and down... need help

[mulletxdriftxx]

my car will randomly start to idle up and down. it goes from about 1000rpm to 2000rpm and it just keeps going up and down. It starts and stops randomly and sometimes it idles up and down very fast. I'm thinking it's the AAC Idle Control Valve. idk what else it can be. help me!!!!

[fregisr]

clean your maf and tps

[mulletxdriftxx]

ther clean

[karmakaze]

clean you IACV with carb cleaner.

[mulletxdriftxx]

i cleaned it and its still doing it

[karmakaze]

i cleaned it and its still doing it

i think your iacv is bad.

[S13FASTBACKSR]

car misfiring or smoking at all? usually when your iacv is bad your car wont hold idle not bog up and down..check your timing and check all of your vacuum lines to see if any of them have holes in them..also clean your TB

[mulletxdriftxx]

the cars not misfiring or smoking. my tb clean . what is the sequence o need to do befor i set the timing?

[S13FASTBACKSR]

well do you know how to use a timing gun? ..if so the 6 markings on the crankshaft pulley represent 5degree's each..the second one from the left is tdc (top dead center) the next is 5 then the next is 10 and so on..the timing should be 15degrees but its hard to check timing with the car idling like that..you adjust the timing with the CAS so what you could do is just move that around and see if the car idles better if it does lock it in..thats one way to tell if the timing is the problem

[chicos240]

I had the same issues, here is what i did.1) checked all vacuum leaks and found one2) Cleaned the MAF connections3) Unplugged my TPS4) Undid the throttle cable5) Took out the Idle screw and cleaned the oring and shot some carb cleaner in the IACV valve.6) Put the idle screw in all the way and came out 3 turns7) started car and adjusted idle screw untill it got to about 900.8)Turn off car...Re hooked my throttle cable to make sure there was no pull on it.9)Turn on car and make sure its still at 900...turn off car10)Hook up TPS and turn car back on voila!

[mulletxdriftxx]

thats not the proper way to adjust the timing u need to do somthings to get the computer ready to adjust it then unplug the tps and adjust it and some other stuff like that.

[S13FASTBACKSR]

works fine for me every time

[mulletxdriftxx]

im not say it ur wrong or anything im just saying thers another way that ive bin told by a few 240 shops but it takes to long 4 them to explan or walk me thru

[S13FASTBACKSR]

yes ive heard of that way too and just like you said it takes them too long to explain..(because it does take longer than i how i do it) and by the way if a 240 shop cant take the 2 minutes it takes to explain to a customer how to time their car correctly i wouldnt be going to them..just my 2 cents

[SRPWR]

Any mods? MIne was doing the same thing, stuck a wideband in it and it read very lean. Be careful!!!!!

[otterman]

Get some tape and just tape the tip of the needle to the tach. That should keep it from moving around

[mulletxdriftxx]

ya i dont go ther any more i just call and ask questions and compare my anwsers with thers. but i already timed it ur way and didnt seam to help.

just a fmic and exhust. wat did u do to fix it?

[S13FASTBACKSR]

check your ecu for codes

[mulletxdriftxx]

how do i check the codes?

[S13FASTBACKSR]

via the l.e.d. on the back of your ecu..turn your key on and you will see it light up..then if you start the engine it will go off (if it doesnt you have a bad ecu) when it goes off you turn the little screw next to the light fully clockwise and hold for 2 seconds and then back fully counter clockwise and you will get a series of slow flashes followed by a series of fast flashes..say there are 3 short flashes then 4 fast ones you have a code 34 ..if you go to the search button and type in sr codes you should be able to find a list of the codes

[mulletxdriftxx]

i got code 55 and thats no faults in memory so im going to just repace all my vacuum hoses and hopfully that will fix it.

[S13FASTBACKSR]

hey man i just re-read your first post, about how the car idles up and down randomly..key word being randomly..thats what made me think..when you have a clogged iacv it wont be randomly it will be constant..but there is also a part on your iacv called the aac which is the auxilary air control unit..this could cause the randomness

[mulletxdriftxx]

so how do i figure out if thats it? and witch one is it the hex shape one or the one with the 2 screws

[S13FASTBACKSR]

you could try checking the ohms and resistance..the resistance will probably check out good but the ohms may be off if thats the problem..i cant remember off the top of my head which wire is the power but with your key on you should be able to find out..thats how you check for ohms and continuity

[mulletxdriftxx]

it was my o2 sencer the one wire only had a cuple strands left so now i just got to clean the iacv and the tb to try to get my idle down

[S13FASTBACKSR]

the o2 sensor was causing bad idle? ive never heard of that..when a o2 sensor goes bad it usually causes richness and you said you werent running rich

[drftsx]

sorry dont meant to thread jack but, my car idles also. it idles roughly at 1500-2000 rpm after driving it around. would it be because im running too rich? or bad o2 sensor? this idling problem is killing my gas lol.

[S13FASTBACKSR]

you should probably start your on topic and we'll all be glad to help you out bud