When I start my car(cold), It revs up to about 1500-2000. It will stay there for a while, then go on an "idle hunt". It will fluctuate from about 1500-2000, like someone is revving the pedal. Then after either you rev the gas, or the engine warms up, the idle is around 500. This is causing low voltage, and dim lights at idle. Everyone says it should be 750 rock-solid. Any suggestions? I just replaced the plugs with ngk-r.
But not the wires, as they look fine. Am I starting in the wrong place?

 

mine does the same thing

 

i dono, mine did the same thing, and for SOME reason if i push the clutch to the floor and just shift it into a gear, the idle drops.. then just pulll it back out of gear and realease the clutch, i dono why, but it works for me

 

hmmmm

 

Sounds like an intake leak or a bad tps.

If its a turbo then check your lower TID hose that connects to the turbo and also check the 3/4 inch hose that goes from the BAC to the thing. its 2 inches long.

 

try just checking your tps, if it's off adjust it that should cure the hunting. as for the low idle if the tps adjust ment doesn't work then just adjust the idle adjust screw on top of the dynamic chamber if n/a. and on the side of the upper intake manifold if turbo.

 

Set your idle from the free online manual at http:www.iluvmyrx7.com Look in the 4A FUEL SECTION.

 

WHen I turn the idle screw, the idle doesnt change. How do you mess with the TPS? and what is it?

 

mine does the exact same thing. the tps is the throttle position sensor it will cure your hunting go here www.fc3s-pro.com and look for the tps adjustment under turbo 2 idle problems section.

 

I dont have a turbo though, does that make a difference?

 

CrackHeadMel: You have a bad BAC valve, or a transmission that desperately needs to be rebuilt.

The original poster's problem sounds like a TPS that is out of adjustment, a BAC valve that is flakey, or need of an idle adjustment....or all three.

 

the fc3s pro how to is for a s4 turbo. I have a s5 n/a. can anyone provide relative info?

 

My car did the same thing. When you have the A/C on, the car doesnt' have an idle up switch so the idle almost dies. You can order a idle up switch from any mechanic specializing in imports and I installed my own. if it always does it even without the air conditioning, then i don't know what your problem is

 

I have my ac belt off, so power isnt parasiticlly removed from the pulley. I am at a loss here.

 

My N/A does the same thing, the idle bounces for a bit but after it's warm it idles perfectly at 750. Is everything fine?

 

This jpg is for setting the tps on a 89, same as your car. If you need to make a light assy from led's from Radio Shack, give a yell and we'll find that site:

 

try resetting the ECU

 

There's something odd about that 500 figure. Any self respecting bac should make that 750. There is a free download of the factory service manual at http://www.fc3s.org/ You have to have Adobe Acrobat 5.0 for it to download. Have you tried adjusting the screw in the bac valve???? See page F1-16 of the Fuel section of the 89 manual at that site. If you can't download it let me know and I"ll jpg one for you.

 

THANKS FOR All your help guys!! I am in the proc of testing remedies. I will followup

 

My 88' has "idle hunt" problem for awhile but then it stopped...however, a new problem came up...when I turned on the AC it would die on me...I took the advice and clean the BAC valve w/ the intake throttle cleaner...Now my "idle hunt" problem came back...but today the idle didnt die w/ AC on. LET ME KNOW THE ANSWER...I TRY TO SELL THIS BABY AFTER IT FIXES...