PO 316 and PO305 codes 2003 Lincoln Town Car

[Carl59]

Make

lincoln

Model

town car

Year

2003

Miles

62000

Engine

4.6 liter

hello,

started car this morning and noticed it was running rough. drove about a mile like that and then the service engine soon light started flashing.

shut car off, went to store, came back and drove home...still running rough, service engine soon light now on steady.

was running fine the day before.

pulled codes PO316 (misfire detected on startup - first 1000 revolutions) and PO305 (cylinder 5 misfire detected )

thank you in advance for your advice.

 

[NickD]

Common problem around here if you get a little water in the gas, my kids don't take after me, maybe after their mother, actually believe that line of BS where spark plugs are good for 100K miles. Depending how you drive, what kind of fuel you dump in the tank with some spark plugs, lucky to get 10k miles.

Yours is a 2003, took Ford a long time to solve head gasket problems, but never hurts to do a compression check.

 

[nickb2]

This, if I remember right is a coil on plug system, so try to move coil 5 to cyl 6, and move plug cyl 5 to cyl 7. They are ALL on same bank.

If misfire moves to cyl 7 swap plug, if misfire moves to cyl 6, swap coil, if misfire remains on 5, injector or need a compression check on that cylinder.

I hope that made sense.

Post back. We are here to help.

 

[nickb2]

Taking compression on a cylinder that has been misfiring is not always the best thing to do. But taking compression to see if it can fire is always good.

But if that cylinder is crudded due to misfires, better to get combustion going and cleanse the cylinder, then take a reading to make sure it is good.


If comp still low, then suspect bad head gasket etc.

But yeah, comp is always good, but first, quickest way to diagnose, swap good know parts. Which are the ones already in the engine.

If this would have been a random misfire, different approach needed.

 

[NickD]

Was running fine then a misfire, any chance did this happen after you added gas to the tank? Don't mention location, entire SE USA had excessive rain from hurricanes. Can of Heet does have a little, with a fuel pressure tester and hot wiring the the fuel pump, can pump gas into a clear container, water is very visible.

With a misfire, doesn't have to be ignition, fuel injectors can also cause this problem the pintle can be struck, bad coil, poor connection, blown transistor in PCM, or even debris buildup caused by returning the PVC hose into the throttle body air cleaner as required by dimwits running the EPA. Also causes the vane in the TB to stick, and if idiots are driving, too stupid to switch of the ignition and get killed.

Talk about tossing dice that's how Ford's misfire cylinder works, trying to detect a slight decrease in engine RPM, can also be caused by switching on your rear window defroster, puts a 25 amp load on the alternator for a spike type load, or the AC compressor switching on. But with a misfire, time to check all the spark plugs.

One of my kids seems to buy vehicles where the entire intake manifold was to be removed to get at the plugs making this more of a five minute job. Another kept on going to a gas station that always has water in their gas.

Coil on plugs aren't too bad as long as they and the connectors were not made in China, PCM's with code stored in flashram is really a bad joke, lose one bit, microcontroller doesn't comprehend an instruction code, crashes, and you are dead.

 

[Mobile Dan]

Be sure to give a close visual inspection to #5 coil boot and spark plug. If you see a problem, replace those parts. https://forestautomotive.net/2018/03/11/misfire-caused-by-bad-spark-plug/

No problem found? Do what nickb2 said.

 

[Carl59]

THanks for the the replies. No, I did not get gas prior to this misfire code.
Going to change the #5 coil and plug .

Seems like the fuel rail is in the way, but I am assuming the coil can be removed
Without the fuel rail removal?

Also, Just to clarify, the #5 plug is the 3rd one from the front on the driver's side ???
Thank you

 

[billr]

No, #5 is the front one on the driver's-side; opposite (same crank pin as) #1

 

[nickb2]

Every ford is the same. Firing order is different, but ford has always listed cylinders in the way bill said.

On bank 1

cyl 1 2 3 4

On bank 2

5 6 7 8

If it is a rear wheel drive, this is pretty obvious if you own a mustang like the one I had back in the day, but with a front wheel or awd drive, saying passenger get crossed with client. Better to say rear or forward. @billr, I am not trying to correct you, I am just trying to tell you that maybe sometimes terminology is our worst enemy. And then, it turns into criminology.

So in your case, cyl 5 is actually the best, since you dont need to remove a whole bunch of stuff or crap as the other nick says to get to it.

 

[nickb2]

Seems like the fuel rail is in the way, but I am assuming the coil can be removed
Without the fuel rail removal?

Yes, you can loosen a few 8mm bolts to give you wiggle room.

 

[nickb2]

The coils will come out.

Of note, plz be carefull when trying to break loose the spark plugs, these engines are and still are notorious for leaving stranded.

I use a 3/8 impact gun to break them loose. For some reason, we have something like four spark plug kits for these engine at work.

I once ask another tech, why do these engines all have really old spark plugs in em, he said, cuz we are afraid to pull the heads. That was back in 2008ish, when they were starting to go out of warranty.

Just saying. Dont use a breaker bar, use a 3/8 impact with low setting.

That is my preffered metod, and the guys at work ask me, why am I not tapping those heads. I say, buy a HD cp 3/8 gun.

 

[Carl59]

Thanks for all the replies and the clarification.
Going to attempt this when it stops raining, although I don't have a impact gun up here, just my ratchet and breaker bar.
Got me a little scared of removing the spark plug and making more problems (snapping plug in block, or having plug blow out later on)
Plugs were changed approxImately 10,000 miles ago....If I were to just change the coil, would this be looking for trouble?

Thank you

 

[nickb2]

If I were to just change the coil, would this be looking for trouble?

no

 

[nickb2]

One thing to do since your not on a boss timer, throw some varsol and tranny fluid in the spark hole. . Let it sit overnight.

I know alot of ppl laugh at me when I mix varsol and tranny fluid, for me, an old geezer showed me this trick, have not found anything that works better than that as a thread seeper

 

[nickb2]

@Carl59, my goal was not to stress you. And since you say they were swapped only 10k miles ago, I would not fret on those plugs. Unless inferior plugs were put in there.

Some ford fans may not like me, but the autolite plugs suck. NGK iridium all day in these engines. I have also read on the internet that autolite plugs are good for fishing. Good sinkers.

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