96 grand am 3.1 L engine occasionally will not start. Try starting about 7am, if it does not start then it will not start until about 3 or 4 pm. Any ideas as to why this is happening?

my guess it does this only cold block. right. a key fact.
glow plugs failing
just because a lamp come on , dont mean much,
actual glow plug current is what matters. (proper)
only takes 3 things
proper compression.
glow plugs
fuel.

What about the fuel, was it drained and the system flushed. Gas turns to goop after this long and will barely burn.

replace your fuel filter and buy Z MAX (only thing i trust) fuel and engine system restore ( about 35 bucks at any auto store but so worth it). what has happend is the fuel in the tank is dirty or carmalized, basically the car had been sitting for a while and the fuel seperated in your tank. normal conventional gas is not strong enough to break down deposits. and when you replace your fuel pump, make sure the whole wiring harness or the actuall fuel pump harness is replace. other wise you keep blowing your fuel pump and/ or keep backfiring

Depending on the milage your timing could be out. Check the timing.

1. air filter dirty. 2. bad engine ground. 3. fuel filter 4. loose connection in ignition system. 5.faulty idle control system.

Try this first, it takes about 30 min to do. 30-Minute Learn Procedure 1. Turn ON the ignition, with the engine OFF. 2. Attempt to start the engine, then release the key to ON; the vehicle will not start. 3. Observe the SECURITY tell tale light. After approximately 10 minutes, the light will turn OFF. 4. Turn OFF the ignition switch, and wait 5 seconds. 5. Repeat steps 1 through 4 - two more times - for a total of 3 cycles of 10 minutes. 3x10 = 30 minutes. The vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch turn from OFF to CRANK Important: Turn the Ignition Switch OFF. The vehicle learns the Passlock Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle. 6. Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password. 7. With a scan tool, clear any DTCs if needed. History DTCs will self clear after 100 ignition cycles. Without a scan tool you may have momentary starter interruptions while history clears itself. Good luck and hope this helps, keep me posted, be glad to help

I would use 10W40 in the 96 and 5W20 or 30 in the 2002.

For the 96 with sluggishness, you need to gently clean the MAF sensor wires with carb cleaner and a toothbrush. It is in the air intake tube. After cleaning, disconnect the battery for 1/2 hour, then reconnect so the computer can relearn the clean sensor. Drive for 10 miles, it will run rough until it relearns.


Section 03-14: Engine Controls, Electronic 1996 Town Car, Crown Victoria, Grand Marquis Workshop Manual
DESCRIPTION AND OPERATION Mass Air Flow (MAF) Sensor The mass air flow sensor (MAF sensor) (12B579):

• is mounted on the corner of the engine air cleaner (ACL) (9600).
• uses a hot wire sensing element to measure the amount of air entering the engine; air passing over the hot wire causes it to cool.
• sends out an analog voltage signal to the PCM (12A650) to determine the intake air mass. The PCM will then calculate the required fuel injector pulse width to provide the desired air/fuel ratio.

The mass air flow sensor hot wire sensing element and housing are calibrated as a unit and must be serviced as a complete assembly.

Mass Air Flow (MAF) Sensor

The problem is the new PCM you installed does not have the correct VIN number of your car.
You may be able to relearn the VIN using the preceedure below, however, there is no gaurentee it will work. You may have to have a dealer reset the VIN for you by way of a scan tool.

1) Instert key into ignition and rotate to run position (do not try to start engine)
2) Leave the key in the run position for 10 minutes until security light stops flashing.
3) Turn ignition key to off position for 10 seconds ( no more, no less)
4) Turn ignition to run position again for 10 minutes until security light stops flashing and repeat step 3 and 4 for (1) more cycle.

The process is a security verification step for the VTD system. ( Vehicle Theft Deterent)

Give it a try, let me know.
Regards,

check o2 sensers and ground wire to them make sure its no corroded if you have v8 engine the groud is under ac unit.

you seem to have either a weak fuel pump or the the TPS(throttle position sensor) is faulty. the tps is located on the throttle body. please rate this thanks