Taking the car in today to get coil #3 replaced.
\
The coil will perform correctly at times, but and this is what is so strange. I can red line the car at 80 and it will seem to work- do it again and get the miss/tug. Once I immediately slow down- more misses and a few pre-ignition sounds and then will straighten out.

As an experiment. I had driven around yesterday and gotten the car hot. Stop at a store and in the parking lot did a quick pop on the accelerator for maybe 3 seconds- not enough to even get it going 15 miles an hour. Just a quick hit- not a flooring and went into this tugging and missing issue. Always showing codes 0303, 1313, 1316.

My assumption, based on guesswork is that the coil should hold a consistent charge as the rest and for whatever reason this one is not and loses it charge, pulse or whatever you call it (I am a layman with terms) more quickly than the others.

I went yesterday as it was nearby and had my new and original cats checked and they showed fine.

Anyone had that type of problem when coming from a high speed and just take your foot off the accelerator and then miss or do a quick pop on the pedal and release and have it go into missing?

I guess that electronics can do anything.

Tom in Dallas
05 S-Type 3.0 76k

 

Never heard of such but there's no charge to hold.

You sound to be describing a fault on overrun, which is a time of big vacuum as I recall. That's maybe the clue.

It doesn't have to be the coil.

 

Are you suggesting a vacuum leak?

Fuel trims do not seem to indicate such at idle or at hard code or at 2500 rpm.

What else could be the issue then. No codes but on misfire #3.

Tom in Dallas

 

I think you just proved that miss-fires are just that miss-fires. They don't have to or need to be consistent.

Combustion is a statistical process. If you use the factory diagnostic gear like the SDD you will see a small amount of miss-fires on just about all cars. In fact your check engine light will not come on until a certain threshold of miss-fires is exceeded. Keep upping the level of miss-fires and eventually the car will go into limp home mode to protect the other components.

The thinking is once the miss-fires exceed this threshold now we need to worry about a failure of some kind and not assume it's just a random miss-fire.

If you have changed the coil once you might have another problem. Maybe the electrical harness is not providing enough power or clean enough power.

There is a TSB from Jaguar and other car manufactures about this very problem. There is so much electrical noise in cars today that it can and does feed back into where it can cause problems. Particularly miss-fires from the coils.

You might consider swapping that coil to a different spot for a while and see what happens. You might also swap the fuel injector to another cylinder for the same reason.

You are gaining nothing by trying to figure out what driving conditions make it better or worse. It does not matter. You have a problem that needs fixed!

The good thing is you have a hard code so chase after that and clear it each time you want to test the car out. Make sure any codes do repeat before doing any work.
.
.
.

 

Thanks. It is so random, it would have to be electrical.
A vacuum leak does not repair itself.
Will not be swapping #3 around as I do not want the learning curve and do not have time It was replaced on July 11 along with all the plugs and #5 for the obvious reasons. Has a 2 year warranty on work- Going to them today to replace. If they find another problem- then good- however it is isolated to one coil/cylinder only. Not even p0300 for random misfires. All relate to p0303, 1313, 1316 as expected.

Thanks

Tom in Dallas

 

Have you replaced the factory IMT O-rings? Your misfire codes are a classic fit in the IMT O-ring realm....

 

They have been replaced by Jag dealer under extended warranty twice that I could tell (proably to get extra money from warranty company)

Why do you say classic (other than what I have read on the forum)? Would it only affect one cylinder? #3 in this case?

Tom in Dallas

 

I experienced the same symptoms with cylinder 3 in late 2009 / early 2010. The dealership tried swapping coils to see if the misfire code would follow the coil swap. It did not. Brutal and Rick recommended replacing the factory yellow-colored IMT O-rings with the new-and-improved green-colored IMT O-rings. Me and my small-handed neighbor buddy did so in January 2010, and I have not had a misfire code since....

I hope you indeed received green-colored IMT O-rings at your dealership. The yellow ones will just fail again. If you hold both colors in your hand, you can easily see why. The yellow ones are thin and more oval than round from a cross-section perspective. The green ones are much thicker, round, and that green color is actually a sealant that forms an airtight seal. They flat-out fixed my misfire issues....

 

I have not personally seen them, but show them replaced on the work orders by Jag dealer twice. My assumption is that they would replace with the correct ones. I am guessing that the reason for the failure is that oil gets into #3, however my #3 when replaced 4 weeks ago showed to be clean of oil and water and I am just guessing they will be the same when looked at this morning by the mechanic, but anything is possible.

Thank for the explanation.

Tom in Dallas