Cylinder 4 rocks! The other 5, however.... 03 S-type V6, 130K miles, P0300 - P0306

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11-28-2009, 09:06 AM

johnxtampa

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Cylinder 4 rocks! The other 5, however.... 03 S-type V6, 130K miles, P0300 - P0306

First post here... what a great forum! I've gotten done reading all pages of the 'Misfire Issues' posting, plus a few others, but my issue seems slightly different, so I'll start a new post.

My wife's S-Type... yes, we are people who have to ask how much service costs, so we "probably cawn't affawd it", but she loves her Jag... To be fair, we have been very lucky so far (great, I just jinxed myself), having had far less trouble than most people have with their Jags.. (I didn't say "none", I said "far less"... ;-)

Anyway, here's what we have....

P0300 through P0303, P0305, and P0306.
Extremely rough running for the first start of the day. Usually, it smooths out after a few minutes, but not always
Sometimes, it seems to run absolutely perfectly when warm
Spark plugs I'm quite sure are the originals
No audible sucking sounds (from vacuum hoses, I mean)... ;-). No visible signs of leakage, etc.
I'm embarrassed to admit having had the dirtiest air filter I've ever seen. I vacuumed it and the car ran great all day yesterday, but at that point the car had also warmed up. I even sprung for a new filter too, and hoped that this morning's cold start would be smooth. It's better, but there's definitely still some missing.

Any thoughts? So far, mine are:

go ahead and give the spark plugs a shot...
Give a can of Seafoam a shot
Other suggestions? (FYI, I did learn about a shop that specializes in European autos, with very favorable reviews, so I'm pretty sure they'll be my mechanic from now on, but I may try the plugs and other things within my abilities first)

Thanks in advance!

Last edited by johnxtampa; 11-28-2009 at 09:11 AM.

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11-29-2009, 10:29 AM

Jon89

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With 130,000 miles on the car, your misfire problems could be coming from multiple sources. If your spark plugs are original, that could be one source (although iridium plugs can and do last for well over 150,000 miles in some applications).

If your fuel injectors and fuel induction system have never been cleaned, that could be your problem as well. The orifices in these S-Type fuel injectors are nearly microscopic and have a tendency to clog and need more frequent cleaning than what you may be accustomed to.

Look for the telltale signs of oil residue caused by leakage from your IMT O-rings. You'll see and feel that residue below your intake manifold if it is indeed occuring. It seems to collect around some of the mounting bolts below the intake manifold.

And finally, don't forget about your coils. Jaguar hadn't quite finished revising the coils to the final new-and-improved version by your 2003 model. If your coils are original, they may be part of your misfire problem as well.

Good luck with your approach and keep us posted on what you do and how it helps....

Last edited by Jon89; 11-29-2009 at 10:32 AM.

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