I took my 2004 Jaguar S type 3.0/6 cylinder (USA) to the mechanic because my check engine light came on as well "restricted" performance" notice came on my dashboard.

They ran a diagnostic check on the car and told me it was misfiring from the right side of the engine (passenger). Though they could not exactly find the reasons that are causing it. I rather just fix it myself to save money. I just want to know the problem. I read other owners have had this problem and sometimes can't find the problem after replacing so many parts.

Here are the results from the Diagnostic CHECK

P0 301
P0 303
P0 305

Thank you

 

Look in the how to here in the S type directory for "IMT O-rings". There are 2 threads about how to check and also replacement. Oh they have color pics to boot.

 

If you intend to keep the car for a good length of time, consider getting your own code reader, preferably one specializing in Jaguars (there's a thread on this forum where there are many suggestions for make and model) as there are some codes that generic scanners cannot report on.

Most choices are $100 or less. Good investment.

 

Welcome to the forum projectjag, I've deleted your other identical post.
Please post an intro in the new members section.

 

Hello, and welcome to the forum. There are many members here with lots of good, helpful information. I'm here, too...

As previously suggested, I'd replace the IMT O-rings first. Get genuine OEM O-rings for this application, not aftermarket. They weren't expensive. Clear the code and see if it returns.

The next thing I'd look at is if oil has collected in the spark plug wells. The plugs share a common well, so a leaking valve cover gasket will short out all coils on that side.

Valve cover gaskets are not expensive. The only downside is access is very poor on the (US) passenger side due to the big swoopy intake plenum in the way. It's not real bad to remove, but a bit intimidating the first time.

If you do find oil there, don't despair. That's a fairly common thing and easy enough to fix with a new gasket set. There's a good chance, however, that those three coils have burned out if trying to fire with the tips submerged in oil. Normally I'd just say clean them off and try them, but it would really stink to have to pull off the plenum again. So I'd say just replace them for peace of mind. At the very least, swap the known good ones from the other bank, as those are super easy to access.

Also, I'd suggest a new set of spark plugs while you're in there. Cheap insurance.

While you have misfire on the mind, you can read my thoughts on the term from another thread when I was up on my MisfireSoapbox(tm)

https://www.jaguarforums.com/forum/s...firing-146818/

 

Thank you for your input kr98664. It is very helpful and I'm going to give it a try. I just wanted to know when it comes to the spark plugs if by any chance do you know the original metal that is used for the S type? Iridium, Platinum, or Copper? Also do you think it matters if I use the original brand or not?

 

Sorry, I'm not very familiar with the in and outs of the spark plugs. When I needed new ones, I simply picked up a set at my local NAPA. I don't remember the brand, material, etc., but whatever was listed in their system has been fine.

If you need better advice, perhaps somebody more knowledgeable can chime in.

 

I believe 3.0 OE platinum. 4.2 OE iridium.

 

Not that I know what I am talking about, I weeded through 6 years of "spark plug threads". Back in the day that I changed out our 3.0 spark plugs with 42,000 miles on them I believe that the Iridiums were spec'd.

Our S Type has about 35k on the Iridium plugs and running strong.

 

Maybe they're just longer-lasting but otherwise good enough. I found the iridiums were quite costly (but for 100K miles didn't care).