Contour Enthusiasts Group Archives Forums General Troubleshooting Can anyone tell me why my car wont idle?

I bought a 96 mystique 2.0 liter with a blown head gasket, i put a new head gasket and intake gasket on it yesterday, but now it will not idle. The car rolls over, fires up and then stalls immediately. If i give it alittle gas, it will run fine but as soon as i take my foot off the pedal it stalls. Ive drove it and it drives fine, untill i take my foot off the pedal, (like while im braking or turning) then it stalls. would this be because my accelerator cable needs adjusting? if so, can anyone tell me the proper way to adjust it? if not, what do you think is my problem? Thanks.

sounds like your TPS sensor is toast and that your car isnt holding throttle.

Yeah, it's sounds like your TPS.

If it runs with the throttle cracked, it's probably the IAC stuck closed. Make certain you reconnected it.

The TPS just tells the computer what the position of the throttle is, but the IAC has to open in order for the engine to breathe. If it doesn't the engine dies.

Steve

ooops this is exactly what i meant in my thread when i said loss of power...i feel dumb now

*goes to search for solutions

where is the IAC located at on these cars? im guessing its on the side of the intake under the intake plenums? the connecter that goes to the TPS on the throttle body has another connector that branches off of it and goes to the part im talking about. if this is the IAC, i made sure it was connected, but i did take it off when i cleaned the intake. would it do that if it had a bad gasket? i reused the old one, it looked to be in fairly good shape. Ill pull it back off and go through it. Thanks.

" if this is the IAC, i made sure it was connected, but i did take it off when i cleaned the intake. would it do that if it had a bad gasket? i reused the old one, it looked to be in fairly good shape."

Yes, bad gaskets will cause bad idle.

IAC cleaning
Zetec IAC location.

For the Zetec I-4, you need to access the IAC from the bottom of the car.

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.

Location of the IAC for the Zetec.

"It's on the back side of the intake plenum under the throttle body area." DESIGN.

I looked at the Haynes manual and the Zetec IAC valve is located next to the starter. Below are the steps from the 1996 Ford CD to remove it .

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).