First step - have the stored fault codes or check engine light scanned - for free - at any local auto parts store; Advance Auto, Auto Zone, NAPA. Then, post a reply as 'add answer' with any fault codes for more assistance.

Possible Causes of Engine Hesitation or Stumble:

Dirty fuel injectors (cleaning the injectors often fixes this)
Dirty air filter (change filter)
Dirty / clogged fuel filter (change filter)
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

Lets get on the same page with explicit facts. You start the car and it starts and runs normal, yes? After running for 2 or 3 minutes the engine stalls out, correct? And then you try to restart it and the engine cranks over but there is no ignition spark. Plug in a code reader and see what fault codes might be stored. This step can't be skipped. Amazon code reader is $20 or less or buy one locally for more money but read the codes somehow.

There is insufficient information here for me to give productive advice. You must plug in a code reader and see what fault codes are presently stored in the computer memory. You may have a PATS fault (Passive Anti Theft System) which can shut off injector pulse and it will not start even if spark and fuel are there. Plug a noid light into ANY disconnected fuel injector connector and crank the engine and see if the light blinks or not to confirm injector pulse or not. Noid light can be bought or borrowed free at most large auto parts chain stores. Code reader can be bought from amazon for $20.

P0715 = Input/Turbine Speed Sensor "A" Circuit. It is not necessary to replace the sensor, a damage/broken wire in the sensor circuit might be the fault.

Check the electric harness located in the transmission. Follow all the wires since the first part of the harness (on engine) up to the end of the harnness (in the transmmision connector), check if they are not broken or shorted (move and squeeze the cables).
Then check if there are no blown fuses.
If all these looks ok; then you have to open the transmission oil pan and look into the solenoid´s harness, check if they aren´t shortened, loosened, or broken.

Yes, the oil pressure switch measures oil pressure inside the engine and sends a signal to the guage or light on the instrument panel.
The most common and safe method to track oil pressure used today is the electrical oil gauge and sending unit. As the oil pressure changes in the engine, a pressure transducer inside the sending unit alters the amount of electricity being sent to the gauge in the dashboard, which affects where the needle sits.

Therefore, it has the ability to accurately measure constant oil pressure safely, instead of simply announcing when the engine is in critical danger. If your vehicle has an actual needle gauge for monitoring oil pressure and not just a light that comes on, then it contains this type of system. On most applications, the oil pressure switch screws into the side of the engine block and taps into one of the oil galleys.

The radiator cooling fans not operating is due to several possibilities; faulty cooling fan switch (temperature sensor), faulty fan relay, faulty fan fuse or wiring / connections to the cooling fans, faulty cooling fan motor.

As a diagnosis and first step run a jumper wire from the positive battery terminal to the radiator fan motor - to see if the motor operates. If yes, then suspect the wirning / connection, fuse or relay in the circuit. If the motor still does not operate with the 12V supply direct, then suspect the radiator fan motor is faulty.

Check the many on-line auto parts sources, such as; www.autopartswarehouse or www.rockauto.com for the replacement parts. For example, they (RockAuto) list the radiator coolant temperature sending unit from around $7.00 for your vehicle.

Your 2002 Grand Marquis 4.6L ingition control module (ICM) is located inside the distributor housing in the engine compoartment. The ignition system is controlled by a signal from the crankshaft position sensor to the ICM and PCM (powertrain control module) to the coils. Each cylinder has a coil on spark plug unit.

There is no ICM in this engine, the coil on plug system is triggered by the powertrain control module aka the engine computer. If you detail the problem you are trying to solve I can help. Buy a code reader and read fault codes also. Amazon has a code reader for $25 and reading codes tales 2 minutes.

Your 2002 Grand Marquis 4.6L ingition control module (ICM) is located inside the distributor housing in the engine compoartment. The ignition system is controlled by a signal from the crankshaft position sensor to the ICM and PCM (powertrain control module) to the coils. Each cylinder has a coil on spark plug unit.

The camshaft position sensor (CMP) is a variable reluctance sensor that is triggered by a high point on the left-hand exhaust camshaft on the 2.5L engine.
Do a test .
Check voltage between the camshaft position sensor terminals PWR GND and CID.
With engine running, voltage should be greater than 0.1 volt AC and vary with engine speed.
If voltage is not within specification, check for proper voltage at the VPWR terminal.
If VPWR voltage is greater than 10.5 volts, sensor may be faulty.


The check engine light doesn't have to be ON to store a fault code.

Check the vehicle for fault codes to see if there are any sensors were involved to the malfunction of the engine.

1.Local auto parts stores such as Autozone ( not in California) or Advance Auto parts will scan and retrieve any diagnostic trouble codes ( dtc ) stored in the powertrain control module for free of charge..

2. Amazon.com has the code reader for less than $19.00 dollars + shipping.

3.Re-post the dtc's in here " answer question " for further assistance.

Note: we need the dtc's to identify the sensor, there are a dozen different sensors to operate the car.

Visit this site and see all the different sensors.

http://www.freeautomechanic.com/car-engine-sensors.html

Navigate to this site and see the code reader
http://www.amazon.com/.../ref=sr_1_1

First, clean the A/C condenser out of debris. Make sure the Radiator cooling and the condenser ( if equipped ) fans are in full operation when the A/C is ON.
Check the low side a/c system pressure, it has to be between 25-45 psi.

The following applies to both types of 3.0L engines, including the DOHC.

When replacing cylinder heads:

Position the cylinder head on the block. Install new cylinder head bolts and tighten, in the sequence illustrated as follows:

First pass: tighten the cylinder head bolts in the sequence illustrated to 52-66 ft. lbs. (70-90 Nm), then back off the bolts 360 degrees.
Second pass: tighten the cylinder head bolts in the sequence illustrated to 45-55 ft. lbs. (34-40 Nm).
Final pass: tighten the cylinder head bolts in the sequence illustrated to 63-73 ft. lbs. (85-99 Nm).

Here's a text version of the torquing sequence - the repair guide has diagrams:

BOLTS - # in sequence

6 4 2 8
5 3 1 7

Might be a cracked manifold housing at this point. Have an inexpensive cooling system pressure test performed - with the engine cold - to determine the leak source.

You can also borrow a cooling system pressure tester from your local auto parts store for free, or a small fee.