Hey guys new jag owner. S type 4.0 109000 got codes for misfire so changed coils n plugs. Went from cylinders 2 n 8 to 5 n 8 now. Car runs good til about 45 mph then stutters abit. What else should I change? Gonna try computer. Thanks

 

Did you change all 8 coils with new ones or just the ones in cylinders 2 & 8? Which spark plugs did you use?

 

If "computer" means the PCM, leave it alone. Not DIY. (They're coded and more.)

Get a cheap OBD tool and start with the fuel trims.

Also, make sure you understand the cylinder numbering as many times people are caught out.

Lastly - well, firstly - how new is the battery?

 

Replaced all 8 coils, used AutoZone platinum plugs, battery is new. Valve cover leaks? Bought cheap coils from Ebay$66. Scanned p0305 p0309

 

I noticed your in NJ - I am as well - I'm sure you meant P0305 and P0308 - Well, the cyl 8 misfire is consistent even after switching out the coils based on what I read above. Those coils from Ebay... hmmm.. possibility some of those coils you purchased on the cheap might not be up to standard. The coils are very prone to mis-firing, especially if you have a center spark well gasket leaking oil into the spark well. The shaking between 45 - 55 is reminiscent of a mis-fire. I would ensure the connectors to the coils for cylinders 5 and 8 (driver's side bank - front and rear coil) are snug. You can pull a coil from another cylinder (not 5 or 8) and swap it in the place of 5 or 8 - if your get a P030X for the coil you switched out then it is a safe bet that coil is bad and a new coil or 2 would be in order. Hope this helps.

 

Gonna order a couple of more coils n switch them out. Will it hurt the engine if I Run it the way it it's right now? My mechanic said he thinks the computer might be bad.gonna fix the valve cover gasket also.

 

Be careful - your mechanic could cost you a fortune if he swaps it without knowing what he's doing and owning the right (expensive) tool. Look up anti-theft on here.

 

What else could it be if it's not the coils or plugs? Bad engine?

 

JagV8 is 100% right - do not let your mechanic fiddle with the computer - I would pull the coils in cyl 5 & 8 - do they have any oil on them? - If you find your coils are the issue replace them with quality units and yes, fixing the cam gaskets, including spark well seals is a great idea as well.

 

I drove my 00 S type with V8 with a bad coil - cyl #4 for a while unknowingly - I experienced the same shudder between 45 - 55mph - I would suggest getting to the root cause of the misfire and not just drive it. Engine misfiring can cause havoc with your cat converter. I would lean towards it being a coil issue, especially since those coils you purchased came off of Ebay. normal amount expected for a set of 8 coils is between $225 - $300 - check the forum sponsers out.

 

Hope you get it fixed! I think you are on the correct path.

Your car has the old style cam chain tensioners that will wear out and fail. This can destroy the engine. Any idea if they have been changed??

After you get the mis-fires repaired please take a look at the secondary tensioners because you can see these when the cam cover is removed. The plastic will most likely be cracked if not completely split.
.
.
.

 

Thanks everyone going to start out with 2 new coils and see where that lands me.looks like someone was searching for the same problem clips in connectors were snapped.when I bought her I was told it had a mis on 8

 

Can someone help me with the firing order. Thanks

 

beluve, it would REALLY help if you would put vehicle specs in your signature ie...year, engine etc.... Look in the upper left hand corner o\f any site page, "User CP" then "Edit Signature" really easy thing to do.

That way the guys here don't have to search around to find that information out!

Help us help you.

 

The firing order is not usually any help or relevance. Why do you want it?

 

Just wondering the coil locations. looking for 5

 

I think I did it, thanks...

 

I believe I covered this before -
cyl #5 - driver's side - 1st coil (front)
cyl #8 - driver's side - last coil.

 

Just double checking thought I saw different on another post. Making sure I don't change the wrong ones..

 

No problem.

2000 4.0 Jaguar S Type cylinder firing diagram:

FRONT OF CAR
5 1
6 2
7 3
8 4
FIREWALL

Good Luck!