I feel that I am chasing a ghost
.
2006 Lincoln Navigator
Check engine light came on 304
Replace the coil pack. And fuel filter
Ran better but still had a miss. (screw holding coil pack would not pull tight)
Light came back on 304 and 305
Changed both coil pack, spark plugs, and injectors.
Light came back 304.
Screw was stripped for cly 4 coil pack so I taped a larger hole and put another new coil pack in and pull tight with new screw
Still a small miss
Now light came back on 304 308
What gives?

Thanks for any help

 

Are you sure the misfire is caused by the coil? It could be spark plugs or fuel injector, as well as other things. If you have a misfire that "dances around" it may be a fuel delivery or an air flow problem. You need to check some live data, like fuel pressure, short term and long term mixture and MAF output as well. You will need to troubleshoot it to find the real cause of the misfire, don't just throw parts at it.

 

Skauber
Thanks
The reason I changed the fuel filter, and the injectors and plugs (btw the air filter is only a few weeks old) was to have all new on the problem cyl.
Cyl 5 stopped with the new coil plug and injector; however cyl 4 keeps coming back even with new coil plug and injector (always the hardest to get to is the problem child) and now cyl 8 has joined cyl 4
I can go buy a fuel presser tester again (and not loan it out as to loose it) what pressure should I be running? I will need to put some miles on it to check the MAF for I just reset the system.

 

You can check the fuel pressure with an OBD scan tool, this way you can monitor it even when driving. If you recently changed the plugs as you indicated, I'd pull the plug out on the offending cylinder(s) and inspect the plug. Did you use the Motorcraft OEM plugs or an aftermarket brand? Aftermarket brands may have to be correctly gapped before they will work properly.

 

Skauber
I really want to thank you for your help. I have ran the truck the last few days and this is what I am now getting.
I have new air and fuel filters on the truck. About 2 months ago they did install 2 new catalyst converters (Jan 9 2018)


CODES
PO300
PO304
PO305
PO308

IM Readings Since DTCA cleared (near 100 mils go and over 8 trips)

MIL ON
MISS FIRE MONT OK
FUEL SYATEM MONT OK
COMP COMPONUT OK
CATALYST MON INC
HTD CATALYST N/A
EVP SYSTEM MONT OK
SEC AIR SYST N/A
A/C REF MON N/A
OXYGEN SENC HTL N/A
EGR SYSTEM N/A

IM READINGS THIS TRIP (ABOUT 20 MILES)

MIL OFF
MISS FIRE MONT OK
FUEL SYATEM MONT OK
COMP COMPONUT OK
CATALYST MON INC
HTD CATALYST N/A
EVP SYSTEM MONT INC
SEC AIR SYST N/A
A/C REF MON N/A
OXYGEN SENC HTL N/A
EGR SYSTEM N/A

 

I doubt this is something specific to one cylinder as it's setting multiple misfire codes including the P0300 which is for random misfire. If you used aftermarket plugs, it could be a problem with the gapping of the plugs. Otherwise it may be a general fuel delivery problem or air delivery problem, including a vacuum leak somewhere. It could even be bad oxygen sensors, though it's unlikely both sides failed at the same time. You'll have to dig deeper with the diagnostics, which would require a scantool which can read fuel trims and fuel pressures and such. Usually a bluetooth OBD2 dongle with tourqe on a smart phone can get you pretty far on that.

 

OK I replaced all coil packs, all spark plugs (Motorcraft), all 4 oxygen sensors, all injectors The Check light has not come back on and she run like a scalded
cat.

Pulled a trailer over 440 miles and still no check lights........ However you can still feel it missing a bit when sitting in gear.