Contour Enthusiasts Group Archives Forums General Troubleshooting rough idle

cold morning, but not the coldest ever. i start my car. it runs fine for a minute or two. then the rpms start slowly dropping down to about 400 rpm. then the it kicks back up all the sudden. did this three times in a row before i intervened and it stopped.

happened once before in november last year. whats the problem?

car is: '99 24V, ATX

try cleaning the IAC, I know people say that about every problem, but it really works.

IAC? sorry, i used to know what it is. but now that i try to think of it, it escapes my memory.

P.S. thanks for the quick replys

Idle Air Control Valve.
IAC cleaning
from Ray's UIM/LIM how to in Duratec Maintenance how to.

"Replacing the IAC gasket:
(From IAC faq)
Over time, the IAC (Idle Air Control) valve becomes sticky due to buildup from the EGR and PCV systems. It can stick partially open such that idle quality is adversely affected, and engine RPM's will not drop below 1500. For a while, blipping the throttle will restore normal idle, but this only works for so long.

The fix is to remove the IAC valve by unbolting the two 8mm bolts that hold it on and disconnected the wiring plug. If you are careful enough, replacement of the gasket will not be necessary. The gasket costs less than US $1.00, so it is no tragedy if you destroy it. Once the valve is off, spray it out with some carb/intake cleaner and make sure any gunky residue is gone. Reattach, and you are done. It is a lot cheaper than a new IAC, which runs around US $70. Note: Ford claims the IAC cannot be cleaned, but this is not true in my experience." Ray.

http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=v6maint&Number=931756&Forum=v6maint&Words=UIM%20aide&Match=And&Searchpage=1&Limit=25&Old=allposts&Main=931756&Search=true#Post931756

Idle Air Control (IAC) Valve


Removal

1. Disconnect battery ground cable

2. Remove the air cleaner outlet tube and resonator assembly.
3. Disconnect the main chassis vacuum line.

4. Disconnect the ignition coil and radio interference capacitor wiring.

5. Remove the fuel line bracket retaining bolt.

6. On 2.0L engine equipped vehicles, raise vehicle on hoist.
7.
7. Disconnect the engine control sensor wiring or fuel charging wiring (depending upon application) from the idle air control valve (IAC valve) at the idle air control valve connector.

8. On 2.5L engine equipped vehicles, remove retainer for engine control sensor wiring from the upper retaining stud bolt.

9. Remove the two idle air control valve retaining bolts or stud bolt (depending upon application).

10. Remove the idle air control valve and idle air control valve gasket.

Installation

1. Note: If scraping is necessary, be careful not to damage idle air control valve or intake manifold idle air control valve gasket surfaces or drop material into intake manifold.

Clean idle air control valve gasket mating surfaces.

2. To install idle air control valve, reverse Removal procedure. Tighten the fuel line bracket bolt to 8-12 N-m (71-106 lb-in).

3. On 2.5L engine equipped vehicles, tighten the retaining bolt and stud bolt to 8-12

4. On 2.0L engine equipped vehicles, tighten the idle air control valve retaining bolts to 8-11 N-m (71-97 lb-in).

so the IAC is the thing after the other thing being pointed to in this pic, right? thats what i want to remove and clen?

The finger is pointing at the IAC valve. You may have to remove the EVR solenoid (black round thing to the left of the IAC when you are looking from the front) to access the lower bolt of the IAC valve. The top nut is easy to remove.

alright, thanks a bunch. ill have to check it when i get home tonight to see what i can do. thanks again

I replaced my IAC, TPS..god I did everything I could but it still idles and dips up and down..Im on the verge of driving my car off a cliff!! Ive ran outa ideas, any suggestions?