Greetings,

I have contacted a few dealers, and they all say the gap listed is correct at 3,5mm (0,14").
Seems all the new NGK sold in Europe are now with that GAP of 3,5 mm ....
I have looked for cross references as well and so... I cant seem to find a proper gapped set.
To add more confussion, I have checked my "vehicle care book" that came with the cat, and at specifications, it says the spark plugs fitted are NGK PFR6G13E, with a gap of 1,3 mm (0,05")....

I'm willing to buy them even if they are shipped from Mars

By the way, the amazon ones you linked to me are unavailable. Thanks for you reply and help though!

P.D. I have recorded a video with my Autel Autolink AL619 showing what I beleive are the fuel trims.
I recorded it while idling, giving a few revs, and holding like 1500rpm and 2000 rpm.
Do you people see anything going wrong with these fuel trims?:

 

It really isn't that difficult to find the correct spark plugs. Just buy a set of NGK 7866 IFR5N10 and if they really have a gap of 3.5mm (which they won't), either adjust the gap yourself, or send them back. You are overthinking this.

 

Well, excuse me but I spent way so many hours to find them because I wanted to make sure about the gap.
Gapping them seems like a "not so neat work" even when I own a very high quality digital caliper.
I called to three different dealers and they all answered that the GAP was 3,5mm, so I finally found the "ones" at Ebay UK, expensive though (170 US $).
The deal is also that the car cannot be driven legally since 25th of december last year, so while I have other car, I have a certain urge to get past the emissions test and enjoy it again!

Now I'm trying to figure out on the Fuel trims that I recorded. Should that be made into a new forum thread?

Thank you for your message Dibbit,
Regards.

 

I wonder if .035" is being incorrectly translated to 3.5mm?

From Jaguar's literature:



I appreciate that the above is for Jaguar part #s, but they will be indicative. 3.5mm sounds far too wide.
Old British weights & measures are, to say the least, bizarre IMO.

Negative LTFT means that the car thinks it's running too rich.

 

^^^^^^ this ! Probably by someone, or some computer, that hasn’t been introduced to the “inch” measurement system.

as I and others pointed out, it’s a misprint. If the person needing plugs would just get the NGK plugs referenced all will be OK, and we put this controversy to bed and can move on to the next issue. I doubt if the plugs will need any additional gapping. None of the NGK plugs I’ve purchased over the last 50 years needed any extra attention.

Z

 

If you look at the code on the spark plug IFR5N10 those last two digits are the spark gap in mm. "10" = 1.0mm.

The other plug you mentioned PFR6G13E has a gap of 1.3mm. NGK ship the spark plugs from the factory with that gap pre set. I think the websites you are looking at are showing the wrong information, or perhaps a different specification, i.e. they aren't listing the gap but telling you some other, irrelevant, information about the plug.

BTW the other letters and digit are the construction type, physical size of the plug, thread, heat rating etc. The bottom line is though that if NGK list it as compatible with the engine, then its going to be compatible.

If I were you I would change the plugs, see what the results are and start a new thread with the new information. As Michaelh says the fuel trims means the computer's O2 readings are lower than expected, so it is reducing the fuel to try and get the balance right. See what happens when you replace the spark plugs, and see what condition the old plugs are in when you take them out. You should also clean your MAF sensor if you haven't already done so, and replace the air filter.

 

As others have advised, you are indeed being supplied with misinformation from whatever gap charts you are working with. The proper NGK or Denso spark plug always comes from the factory with the correct gap pre-set....

 

Don’t get offended, we are only trying to allay your concerns regarding the spark plug gap.

a digital caliper isn’t normally used to set the spark plug gap, don’t really see how it could be either.

There exist many tools for setting the gap. Most auto parts stores have them in a big bowl on the counter. Cost is about $5.00, there are some more expensive but most of them are under $10

this is one type from Amazon :

 

Blues Dude... Gaping spark plugs is easy and something you can do...and I would just say this (in agreement with others) you will find LOTS of inconsistencies in the online world for car parts. It will throw you for a loop at first,,, and longer. Also, in ways you can and that make sense to you take what JAGUAR dealers say with a grain of salt. In ways and for reasons they are working from a strange set of motivations and experience - they often don't know it all,,, and love to take your money.

Folks here are motivated by years of gathered and worked for experience and are motivated SPECIFICALLY and only by a love for the cars (lol,,, and in some cases ego &#129315. It's all good. Gotta love it. Try not to take things folks say here personally. Just folks trying to help.

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Yes, I'm working on all this. Seems I got a bit nuts with the huge ammount of info and websites with different data (also when pictures show a different part number than the one supposed to be sold there... I immediately close the site )

Thank you everyone for all the great information and support! Appreciate it

Regards from Spain