i got some possible causes last time i asked this and tried all of them. right now my idle while driving is 1300-1400rpms when iam at a dead stop. i checked the slack and tension on the throttle cable, changed TB gasket, changed all vacuum lines on mani,checked idle adjust screw, checked for throttle plate sticking,cleaned my IAC valve and its still the same.

what else could make my idle while driving do that? and when im in park(auto) it fluctuates from 800-2000-800-2000 etc.

allready got new plugs,new wires,new cap,new rotor

this is so urking.

car is a 96 civic ex auto.

please let me know whats going on if you can think of anything.

thanks
james

 

The cause for a fluctuating idle like that is usually either air in your cooling system, a vac leak, or a bad IACV.

 

did you check your fast idle thermo valve and the egr valve? Although the egr valve having carbon build up might be more consistent to where the idle will stay high all the time because it gets stuck open..... but yea like inpyral said check for air in the cooling system, fluctuating idles SUCK because there are so many things that can cause them, so knock out the cheapest/easiest things to check before you start replacing things....

 

where are these located on the Y8 auto?

 

you dont have a fit on the y8 in that car...youll know the egr valve...i cant remember exactly where it is, but its on the intake manifold somewhere. to test out the iac problem...well if its giving you that code, drive one just like it and swap it out just to see if that fixes it

 

Y8s dont have EGRs. only Y5s.

 

I had a similiar problem.

It would drive normal, but it would idle between 1500 and 2k sometimes, very annoying. It ended up being my TPS sensor. I replaced it, and the problem was fixed.

1stGenCRXer helped me out with that one. Christ, is that guy still around, I so need his help again....

 

what is the normal operating life of a TPS? 5-7 years?

 

TPS usually lasts the life of the motor unless you over volt the sucker or otherwise damage it.

 

turns out it was the iacv but i used the TB that the iacv was on, and now the throttle plate sticks sometimes. like i have to push the pedal hard the free it up, tried lubricating it and it still does the same.

what could it be? maybe throttle plate wasnt deburred properly?