Hello everyone,
I have a 2003 Jaguar S type 4.2, 8 Cylinders.
Check engine and Restricted performance have been popping on my dashboard.
I have taken the car to multiple mechanics but not ending fixing the issue.
I have changed already the catalytic converter, the MAF ( mass airflow sensor), and the spark plugs.
I am looking into changing the Ignition coils, fuel injectors, and the oil filter.
What would you guys recommend per your expertise?
What could be a different issue than these?
Is changing the listed objects above DIY -oable?
How to change the fuel injectors and what are the steps?
Should I unplug the battery?
Where are they even located? lol
Newbie over here
I am going to attach a picture of the OBD II scanning and the issues founded.







And thank you in advance if you could help

Are these the right fitment?

 

Leave the injectors alone!

They are low probability items at this point.

I can't see if it's running CL (closed loop) or any LTFTs so can't say whether you've any air leaks, but the misfires are a worry.

Did you have them BEFORE you took anything apart / replaced anything?

I ask because there's a chance some of the work has made things worse.

By all means change the oil filter but 99.9% it's not going to affect the codes.

The cyl 1-3 coils are more of a suspect than anything else right now. Any signs of contaminants on them / the plug tops / plug wells?

In case you get more coils (or just 1 to start with) be careful to avoid any which may be of suspect make because they'll likely add yet more trouble. (I'd get a proper new one or even used from a breaker ahead of a cheapie one.)

 

Pull some plugs and see how they look

 

Oh - I REALLY hope the right plugs were used!!

 

so many things to check but plugs are easy. Could be gapped wrong. Could be wrong plug. Could be something other than oem. Could be broken. Could be loose. Could be sitting in water. Might be a bad connection. Or bad coil.

but if the plugs are carboned up bad for the air leak theyll misfire. Gotta check and check the gap!

 

The right ones are pre-gapped

 

Thank you for replying and the help!

All right I will leave the fuel injectors alone.

Yes, the misfires were there before the changes made.

And I actually agree with you regarding the wrong work, because I don't think the catalytic converter is attached correctly, which would malfunction the O2 sensor and vacuum leak. Right?

Alright will change the oil filter, but I know I need to unplug the battery before doing that, anything else need to be unplugged?
(And if I don't have the radio password what should I do :/)

I have barely been able to remove the ignition-on-plug cover. But it does seem that The Ignition Coils are Different than each other.
I have bought these Ignition Coils, what do you think?
Are they the right fitment and form per your expertise?

 

They do look different than each other.

 

No need to unplug the battery to change the oil filter!

You'll need more oil, of course.

As you've realised, you do need no air leaks in the exhaust, cats included.