idle problem

I replaced my pcv so its not that i also replaced my iac so its not that and it still idles high same way. heres exatly what happends. i also only had the new iac on for about 25 miles should i have left it on? i figured since it didnt make a difference instintly then it cant be a stuck valvle like i thought. what else could it be what else can i try? how can i check to see if my mass air is bad or what about that other sensor in the elbow? also whats that black piece thats connected between the elbow and the iac? its a black box in the middle of the 2 hoses connected to it?

So here are what itsdoing.

1-when i start the car cold, it'll idle at around +1200RPM, and come down to about +800RPM as engine worms up(this is normal). as soon as you starts to drive around, it will not idle at 800RPM. But idle at +1000RPM. and stay there until i shut off the car again, and starts it back up. then it'll idle again at +800RPM, and repeats what i'v just discribed.

2-when i'm idleing at either +800RPM or +1000RPM, if I turn A/C on, then idle will come down to about +750RPM(this is also normal)

3-Either with or W/O A/C on, and regardless of idle RPM, if i brip the gaspedal in neutral, it'll stop at around +1600RPM. It'' raise RPM with this sound of air serging(I guess). and hang there for about 2~3 sec, and then comes back down to what ever the RPM was previoulsy(either 800RPM or 1000RPM. If i only give the gas until about 1100RPM, and let it go, it'll continue to rise its RPM until 1600RPM on its own. This suck azz, because....

5-Appearently, this serge of Idle is going on even when I'm driving around in any gear. Infact, i can drive around in 5th gear(or any gear for that matter) at around 1200RPM without touching gas pedal. its like having crouise control on.

6-While I'm driving around at any speed, and i disengage clutch, RPM will stay at 1400RPM. infact if i'm coasting down to stop in neutral from any speed(25mph ot 65mph), it'll stay at 1600RPM until i come to complete stop. then once i'm at complete stop, it'll stay a 1600RPM for about second, and then come back down to 1000RPM(Or 750RPM if I have A/C on.

7-While i do number 5 above, sometimes RPM will fractuate up and down between 1600RPM and 1000RPM. wen its dropping RPM from 1600RPM, it'll make sort of gerggle sound - and as soon as it hit 1000RPM, then it'll shoots back up to 1600RPM, then starts to come down, to about 1000RPM with sound and repeates itself.

yep i used new gasket. also that iac mod wont help me cause im throwing the idle over speed air code.

update i took the harness off of the mass air sensor and it tried to die for like 2 seconds then idles back to 1000rpm does this mean its a bad mass air or good?

i also took the harness off of the tps and the iac and it still idled at 1000

mity2 said:

Did you copy my old thread? You are having exactry same probrem that i had with my car. And It was PCV valve. After you replaced PCV and rubber gasket, did you reset youyr PCM? Check yout TPS voltage? And anyother intake leak in general

Oh and after you re-set PCM it takes little time befor it relearn everything by the way

Click to expand...

yea i pretty much copied your thread because im having the exact problem except my rpms at at 1600 not 1400 also i did reset the pcm and the tps voltage is at .98 what else could it be? could my plastic intake be leaking?

mity2 said:

No i meant like your TB ot Elbow, Elbow to plastic intake that connection. And also hose that goes back of elbow, EGR connection things like that

Click to expand...

im confused on what you mean are you talking about the rubber pieces connecting the elbow to the tb? i have a cold air intake on it so its not the stock one.

mity2 said:

No what i'm talking about is where elbow goes on plastic intake. there is rubber gasket there. and TB to Elbow connection, there is gasket there too. And EGR connection, there is also a gasket there. PCV hose connect to front of elbow, and also there is a hose attaches to back of elbow. and ofcourse IAC gasket. there is all these possible leak. I'm tellin' ya to check all of them - basically everything that you did when you installed elbow. check them all

Click to expand...

ok i get what your talking about now. when you say elbow you mean plenum. ok the tb gasket is new, the intake blue gasket (ring size of plenum) looks good no cracks or anything, new pcv, the only gaskets are the iac and egr i tried new iac and used gasket no improvment so i removed, egr i didnt replace cause it looked good.

mity2 said:

Ya try that. And also while car is idleing, disconnect IAC if idle become normal, and no hang up

Click to expand...

hay i really appre*****e all the help thanks. the tps is set at .98 its verry hard to get it lower should i attempt it? also when i disconnect the iac nothing happends idles the same except the rps come down faster when reved and i also pulled the plug from the mass air sensor and it tried to die for like 2 seconds then it idle'd back to 1000

wait the tps sensor has a gasket? if so i dont have one that could be it is the tps supposed to have one? also where can i get new screw heads for the tps mine are pretty much gone.

couple days but the chk engine light came on again and same code

hay guys thanks for all the help i got it fixed. you never would belive this but my 70mm tb was causing the problem. i put the stock plenum on and it still idled the same way so today i got fedup and put the stock tb on and it fixed the problem. anyone ever heard of a defective tb? thats wierd to me. also it was so easy setting up the tps on the stock and the aftermarket was hell just to get .99 why is it so much easer with stock over aftermarket. also why would the tb be the problem? o yea i did removed the tb when i switched plenums so it was tight i think the ford racing tb is defective. or could it be the fact i have a computer thats from 99 instead of the newer ones. maybe a flash could fix it.

its the tb nothin else as soon as i reinstalled it it idled the way it used to. its not the tps the tps was set at .985 both times.