Stall when press gas slowly

My car starts and idles fine.

But...

In neutral position, if I press slowly the gas pedal to 1/8 of the pedal's stroke the rpms drops and car wants to stall, if I keep the pedal at the same position car will stall, if I press more quickly then revs rise, if I release the pedal it return to normal idle revs.

In drive position, if I press slowly to the 1/8 of the pedals stroke, the car have the same behaivor than in neutral, if I press quickly, acceleration is not progressive, first 1/8 to 1/4 of the pedal's stroke nothing, then suddenly gives a very sporty jerk

First I suspect of the TPS and tried a known in good condition sensor, that didn't solve the problem.

Then I suspect of the Injectors wiring harness, so I did a CEG's repair (lots of electrical tape and some butts conectors ) problem persists.

I don't know what to do next.

Any thoughts?

I will appreciate any input.

My car is a 98 Contour ATX 2.5L 65K miles

TIA,

-Jorge

Sorry, I forgot to tell.

CEL turns on after some stall attempts but it turns off next car start.

-Jorge

IAC 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.

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).


IACvalveduratec Idleaircontrol IACvalve

Thanks Tony.

I will do that tonight.

-Jorge