Sooo; my wife was driving car on freeway in beautiful sunny CA and said it started stu..stu...studdering and p...p..puttering a bit. so when she made it home on a prair. I test drove it and just as discribed. so i ran obd test.
my question to all of you in jaguar heaven is. should i just start by replacing the plugs & coil.. also where is the #5 coil located? (what side of engine). also read error code P0456 went off, small vaccum leak.
thank you in advance for any helpful info.
Ps: this is an intermittent problem. not constant.(the misfire)

 

OK, we need to know which MY (Model Year) and engine - 3.0, 4.0 or 4.2 - then we can assist based on the above info - thanks!

Update - Just read your intro post - 2002 S Type w/ 3.0 V6 (pleas eget this info into your signature line) - I'm not a 3.0 expert but reading through I understand the IMT - O-Rings can be the cause of misfiring coils.

Also, the usual suspects: oil leaking into the spark plug well and the coil(s) going out themselves.

I would first swap out the coil in cyl #5 (rear passenger side?) with cyl #3 and see if the P0305 becomes a P0303 (cyl 3 - misfire) if it does you know your chaning out a coil - also, when pulling out the coil - look for oil residue on the bottom of the coil - if oil is evident - you will need to change out the spark well O-Rings and the cam cover for safe measure.

I'm sure the 3.0 experts will chime in further regarding the IMT O-Rings and P0456 code.

 

oh yes, it is a 2002 Stype 3.0 with 77,000 original miles.

 

im sorry, being new to this forum i thought it may have already posted my vehicle info.
i quick replied my vehicle details oops! haha. thank you

 

ooh, so i see as it may have been a small oil leak causing the foul. yes when the engine gets hot it would drop a bit of oil onto the exhaust manifold and a small puff of smoke would insue just at the rear of the passenger side valve cover area. hmmm very helpful i will keep this in mind. thank you

 

one more thing, where is the signature line located (how do i insert that info)

 

Click the "user cp" link in the black bar at the top of each page, then click the "edit signature" link in the bar at the left of the page that opens, fill in the details and save the info before you close the page.

 

In a 2002 car it could be a persihed vacuum hose. Try Search with
hose elbow

Coil might be #1 to change.

 

The 3.0 V6 is prone to having oil leaks from the cam cover gaskets and spark plug hole seals, which will cause the coil packs to short and result in the condition you describe above.

Changing the RH cam cover gasket, spark plug seals and coil packs requires removal of the inlet manifold. If you decide to do the work, it would be a good idea to also replace the spark plugs and the o-rings on the inlet manifold control valves.

Underneath the inlet manifold, there is also a rubber elbow for the crankcase breather system that over time will perish and collapse, so that should also be replaced when the manifold is removed.

Refer to the Jaguar Workshop Manual for the correct cylinder designation or perform a search on this forum.

 

i appreciate the information and will keep it in mind.
as of now... i replaced the coils on passenger side. then i replaced all plugs with NGK iridium. and also the o-ring above coil #5. it seems to be purrrrring like a kitten. i will pay close attention to any sighns of misses or idle fluctuation. thanks to everyone in the forum.