97 Crown registers (computer) has not reset after 2 weeks? Codes stated P0302 and P0308


Asked by Feb 02, 2017 at 01:28 PM about the 1997 Ford Crown Victoria 4 Dr LX Sedan

Question type: Maintenance & Repair

97 Crown is missing in cold weather (mornings 50 degrees) and during the
evening ride home (70 degrees) it runs great with no miss.  Coil packs,
plug wires, plugs are 300 miles new, all injectors firing.  Air filter and fuel
filter clean; MAP voltage 11.5 volts, idling in gear .8.  Garage has no clue
other than coils are bad.  I am on my third set of coils and second set of
plug wires.  No vacuum leaks or leaking coolant.  Missing in the cool
mornings and runs great is warmer weather.  I keep thinking some sort of
ported vacuum switch or some sensor is out in the cold and works in the
warmth.  Any thoughts of what I am missing.  Garage can replace parts
until it runs good, but so can I.  As Tracy said “Shot gun approach”.  All
information appreciated………………..Grump L. Co 3/5

8 Answers


If your vehicle has an Ignition Control Module (ICM), then the most likely cause is that the ICM is BAD. If your vehicle does not have an ICM, this means the coil pack is controlled directly the PCM (Powertrain Control Module= Fuel Injection Computer) and the PCM is probably fried.

1 people found this helpful.

Thanks for the info. Today it is not firing 2 & 8 injectors (cold). It is if the system cannot compensate for the weather. PCM gets blamed but it is not always the trouble. I am pretty anal about about resting, just running out of things to test. Vacuum steady 20 inches, no leaks. I believe dead miss on plugs, wires or coil would be constant. Registers not resetting is suspect, if I am saying that correct. I cleared the codes two weeks ago with jumper from pos to neg for 15 mikes. CEL cleared than came back. Heard PCM going bad will not throw code. Last codes were P0302 and P0308 which lets me know injectors are following the problem. Replaced secondary parts with no differennce and hate to do the same with PCM. Appreciate your info and dig the Comet. My GTS is one of 44 made. Been garaged for 26 yrs. just needs paint and replacing camshaft with Comps 268 extreme. Why do I wait.? Grump out.


Try drying out the spark plug wells and then seal the coil boots to the spark plugs with dielectric grease. Also seal the coil boots to the spark plug wells. Maybe condensation is causing the coils to arc to ground.

1 people found this helpful.

Will give that a try also. Thanks for your input...........Grump


Yes, plug holes dry, coil springs pulled long to reach plugs. Will put grease in boots to seal plugs. I tested the MAP sensor following this linkhttp://troubleshootmyvehicle.com/ford/4.9L- 5.0L-5.8L/how-to-test-the-map-sensor-1 which was straight forward. MAP seems fine and not throwing codes. Will check all wire connections, clean and wire brush grounds and see what happens. Then take to O'riellys to get for registers to see if computer reset and will try my garage to see what their scan states. O'riellys could be defective but sticky to one scanner until mine comes in today. Thanks for all your thoughts and will try them all and keep you posted. You out there Tracy?


ATM, my thought was the engine runs bad cold and good warm. Temperature I think is a factor. I know there are two water sensors in the intake and both have continuity. May not mean anything if not in range and not throwing codes. After a weekend of cleaning, check plugs and gap, seating plug ends down and hear click (no springs), grease on the end, all ground straps removed, wire brush clean, tightened. One code remains (P0354). I am reading up on the MAT now, but if you have some intel I could use please share. It has got to do with temperature and leaning toward PCM. They do get blame but looking at all alternatives .............Grump


Okay, cleaned MAT and MAP, soft brushed them clean. Read article and said MAT and water temp should be a few degrees apart. Water temp 188 and MAT 72. Out of range, will purchase MAT on the way home today and replace am Saturday. New code stating EGR and ICT were acting up. May have been caused after spraying sensors above clean, never came up before. Will check and clean ICT and EGR, test to see if working properly. I believe the MAT will make a difference and report back on findings.


MAT and MAP is good, leaning towards PCM being bad. All test show components good and within range. Same codes keep coming up. P0302, P0308, P0351, P0352, P0353, P0354. Car runs great in warm weather, missing in cooler weather. If all codes above remained consistent I would say coils, wires and plugs are the culprit. Since it does not always stay the same it could be the PCM. Searching for one tmrw.

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