2001 Ford Mustang Faulty fuel injector symptoms not resolve

Hello,

Ok, since it is a 2001, just about any problem will turn on the engine light. So, is engine light on? If so to narrow the field will need to pull codes.

A couple possibilities are.

Ignition Control Module - Failing once warms up

Coolant Temp Sensor - Failing once warms up

Coil or Coils - Depending on if it has Coil Overs or a Coil Pack.

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How far is the nearest parts store or do you have a good scanner.

Since it is what could be concidered an intermittant problem, some scanner won't read them. However, your local parts store should be able too.

Another possibility is the Idle Air Control Valve.

The Idle Speed Control (ISC) valve, also called an Idle Air Control (IAC) valve, is used on both throttle body and multipoint fuel injected engines to regulate idle speed.

To Test

turn the engine off, unplug the ISC bypass air solenoid connector, then restart the engine to see if the idle rpm drops (it should if the ISC solenoid is working). No change would indicate a problem in the motor or wiring.

The ISC solenoid can be checked by measuring its resistance. With the positive lead of a digital volt/ohm meter on the VPWR pin and the negative lead on the ISC pin, measure the resistance of the solenoid. On many applications, the spec calls for 7.0 to 13.0 ohms. If it is out of specs, the ISC solenoid is bad. Also check for shorts between both ISC solenoid terminals and the case.

If the ISC checks out okay, check for battery voltage between the ISC connector terminals while the key is on. Voltage should also vary when the engine is running. No voltage indicates a wiring or computer problem.

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Ok, appears the IAC is good.

I will ask the other techs to post test proceedure for the other components and the thoughts on your problem. I don't have access to my to get the proceedures. I am out of state for a few day.

In mean time if you can test the TPS (Throttle Position Sensor).

You can measure the sensor's output voltage by packprobing the sensor conenctor with a voltmeter. First, check for the presence of voltage at the TPS with the key on. The TPS cannot deliver the proper signal if it does not receive reference voltage from the computer. Refer to a wiring diagram for the reference connection and look for 5 volts.

The second check is the base voltage reading. Compare the voltage reading to the manual specifications. TPS voltage values are often specified to the nearest hundredth of a volt, so if the base TPS voltage reading is not within .05 volts of the specified value, adjustment may be needed (if it is adjustable). If it is not adjustable and the reading is out of specifications, replace the sensor.

The third check is for the proper voltage change as the throttle opens and closes. Voltage should rise smoothly from about 1 volt to a maximum of 5 volts at wide open throttle. No voltage rise or skips in the reading means the sensor needs to be replaced.

Did you actuate the Thottle while test each pin? If not do so and post results.

Engine Coolant Temperature Sensor Test

Engine Coolant Temperature (ECT) sensor uses a 5-volt reference voltage during engine operation. To check ECT signal voltage, backprobe between signal terminal and ground with engine running. To check sensor resistance, disconnect sensor connector and measure resistance between sensor terminals. For ECT sensor specifications, see ENGINE COOLANT & INTAKE AIR TEMPERATURE SENSOR SPECIFICATIONS table. For additional testing information, see TEST DA under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - CNG & GASOLINE article.

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Sorry for delay getting back with you. I was out of state with wife who had hip surgery and we came home yesterday.

Anyway, now that there is a code before you do any part purchasing lets do a test.

First do your car have a coil for each cylinder? If so take the #3 cylinder coil and swap it with another one. To see if the misfire moves. If misfire moves then replace coil. I misfire does not move need to do some more tests.

Post finding.