The check engine light came on. The car runs like crap when I romp on the gas and then the limited performance light comes on.
Any ideas please!
Thanks,
Cheers.
Bob
This is the 2003 STR

 

E-diagnosis Faulty coil. or fouled plug. swap the coils one up see if the CEL code follows the cylinder.

P0308 V8 EMS
OBD II
Misfire detected – cylinder 8
*Refer to Misfire Note, page 6
Misfire monitor drive cycle –
page 6
1 or 2* N None — Refer to P0300 Possible Causes

P1314 EMS
OBD II
Misfire rate catalyst damage –
bank 2
NOTE: This DTC will flag only
when accompanied by an
individual cylinder misfire DTC:
P0300 – P0308
Misfire monitor drive cycle –
page 6
2 A ECM Default:
– Maximum engine speed
reduced
— Cylinder compression low
Worn camshaft / broken
Fuel delivery pressure (
Fuel injector(s) restricted
Fuel injector(s) continuously
Fuel contamination
Fuel injector circuit fault(
(Injector DTCs also flagged)
Spark plug failure / fouled
ECM to ignition coil primary
(Cylinder misfire detected
flagged)
Ignition coil failure

 

Where is cylinder 8 and what is the part number/cost of a coil?
I know, cylinder 8 is the one that is impossible to get to?
Thanks,
Cheers.
Bob

 

Get the DTC file(s) from the FAQs and see

The FAQs are really useful.......

 

cyl.8 last plug back toward firewall on drivers side.

on the 4.2 non supercharged all the plugs are easy to get too. On STR I don't know

plug order is as follows.

passenger side from standing in front of the car looking back is 1.3.5.7

drivers side front to back is 2,4,6,8


cost of a coil is around $70 go to ebay or rock auto
http://www.rockauto.com/catalog/raframecatalog.php

 

Thanks.
I'm off to the dealership to get new spark plugs and a coil.
I don't think the plugs have been changed in 8 years and 70,000 miles
Perhaps this will do the trick, get the horsepower back under the hood and clear the codes. I watched Vance580's spark plug replacement video.
Bob

 

Plugs not due till 100K miles so should be fine. The coil is #1 suspect - dirty/wet/just bad.

 

maxthrottle, please read the New Member link in my signature, and reply to me either by PM or this thread that you did, and will comply.

 

Roger Wilco H20boy.
Bob

 

appreciate it maxthrottle, thank you.

 

Just a comment. Inspect all the coils and boots when you look at #8. The valve covers have round gaskets that prevent oil from getting to the plug/coil and these can leak with age. So if ANY oil or fluid of any kind is found when you inspect the coil. Be sure and change the cam cover gaskets. These will come with the plug well seals too.

At your age and miles it is very possible. If everything is dry just replace the coil. The coil should come with a new rubber boot but check and change the boot also. It's cheap and you don't want to get in there again if possible. Be sure and use dielectric grease between the plug and rubber boot.

With the miles mentioned I would always replace all 8 plugs. Please use the factory plugs if possible.
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I bought a coil and 8 spark plugs from the dealer.
The coil has the integral rubber boot
I plan to dig into it tomorrow. I didn't think about the valve cover gaskets, I hope everything is dry and its just plug and play.

 

Just as an extra precautionary step, get a spray can of CRC Di-electric and start spraying all over the wires that are connected to the coils and connectors to remove moisture and dirt from them. Just make sure your plug wells are covered when doing this

 

I removed the #8 coil and it was coated with oil, I replaced it with a new one after replacing the plug. The plug looked OK for 70K and 8 years.
The engine runs much better now but the CEL liight is still on, I dont have a reader so hopefully this will go away after a few dozen miles?
Instead of removing the rest of the coils and changing the other 7 plugs I'm going to wait and get the valve cover gaskets. From all the tubes and bracketry in the way this looks complicated, but it may be the only way to keep the oil out of the coil holes. So, what's the proceedure/time and expense for this operation?
Thanks.

 

It won't go off so soon. You can read jag's statement in the FAQs or just keep driving. In round terms, it'll need 3 separate cold-to-hot drive cycles with no further issues.

 

What a great forum. I have a 2001 XK8 with a P0308 trouble code which indicates cylinder 8 misfire detected. Car has 113,000 miles and I purchased the car with 80,000 miles.

As I see it a good move would be to replace the one coil for cylinder 8, change all the plugs (I have not done it and guessing it was not done before).

Any suggestions or advice would be appreciated.

Cheers from Minnesota

 

Do the coil, for sure. The plugs... this is the S-Type forum and I know one of our V8s from 2001 would be a 4.0 with something to really worry about: tensioners. I don't know about the XK8 in that regard but suggest a good trawl around the forum for it!

Can't hurt to do the plugs, except maybe your wallet if it turns out they were already changed.

 

Be sure to get those cam gaskets and spark well gaskets changed out ASAP - so your $$$ investment in that new coil doesn't go up in smoke... oil leakage damages those coils rather quickly...

 

abonano has a very good point!

Once you found oil in the plug well I would stop driving it if possible until the gasket change.

Watch especially for a flashing check engine light. That means the current conditions could possibly damage or destroy your catalytic converters. The misfire dumps unburned fuel in the exhaust where it's burned in the converter.

Just depends on how much fuel and for how long before converter damage occurs.
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