I originally posted this in the new members area, folks told me to post it here instead.

Hello everybody,
I just brought my 1998 XJ8 Vanden Plas home, and it is a beautiful car. The mileage is a litle high (145K), but the body and interior are immaculate.

I am getting some warning messages, along with some weird driveability problems. The check engine light stays on and I get the "Restricted Performance" error as well. The car will not rev past 3,000 RPM and it is very tough to accelerate. From the limited reading I've done so far it seems that when the car is in this more the engine is running in a fail-safe mode, I'm guessing similar to when a GM car runs in open-loop mode when something is amiss. I'm awaiting my friend to come over with a code reader and I'll post the codes once I'm able to.

In relation to the above problem, sometimes the check engine light will blink, and the car becomes exceptionally undriveable when that happens. It only happened to me a few times on the way home, and it only lasted about 30 seconds.

On the drive home I also got an "engine coolant low" message, although the temp gauge never went past halfway. I tried topping off the reservoir and it seems to be OK now. Is there any particular procedure for filling/bleeding the coolant system?

And lastly, I am getting the "traction control fail" and "stability control fail" message lights, as well as the ABS light coming on. I'm gonna guess that the ABS system is the root of the problem since the traction control would use the ABS system? Also, what's the difference between the traction control and stability control?

Thanks to anyone who can help, or point me in the right direction. I've literally owned this car for not even 5 hours now and I just found this forum. I will also keep digging through here to see what I can learn.

 

Do yourself a favor and read the OBDII codes first and I am certain we can help. Any AutoZone, PepBoys and or Sears will read the codes for you. FYI When the car goes into Restricted Performance or Fail Safe it will restrict the RPM preventing it from over revving. However you can drive it gently. You will soon find out that the gauges are nothing but a placebo, they will give you the high and the low but the rest is in the middle range.

 

I got a code scanner hooked up and found the following codes:

P0304 - cylinder 4 misfire detected
P1313
P1316
P1000

When I cleared the codes using the scanner the check engine light went out and the car wasn't in RP mode for a while. We did some searching on here and saw that each cylinder has its own coil. So I took the coil access cover off and switched the cylinder 1 and 4 coils - that way if it's a bad coil the problem will follow the coil.

I put everything back together and sure enough, after about 10 minutes of driving I got the same codes, except the first code now reads P0301 - cylinder 1 misfire. Looks like it is in fact a bad coil. I have one coming in that we ordered off of Ebay.

When I replace the coil I'm also going to replace the spark plugs, since I'll have that cover off anyway, and I have no idea when those plugs were changed. Does anyone have a recommended brand of plugs? Also, is there any special gap size to set them to other than what the parts store lookup has for them?

Thanks

 

You can get the coils from NAPA or AutoZone if needed. As for the plugs it is a subject that has been brought up many times. Whatever plugs you install make sure they are for that car and check the gap prior to installing. This link should help Questions and answers about spark plugs. The good and the bad. - Jaguar Forums - Jaguar Enthusiasts Forum

 

Thank you very much for your help, Gus!

In what you said about the gauges, are you referring to the temp gauge? That makes me a little nervous now if I can't really trust it.

 

You just need to be aware that they are not what you think they are. When it or they go into a zone outside the normal (middle) you need to look at it and find out why. It is not a major issue just know that you need to act quickly.

 

Welcome -- you do seem to have many of the common faults from the early cars.

Do a search on the plugs -- many are using the iridium plugs. The x308's prefer a conventional plug design as installed from the factory ... I do not think you can fix the gap on the iridium?


The temperature gauge is programed to stay in the middle over a wide temperature range -- basically all it is telling you is that the car has warmed up and that it is operating within a range from about 185 - 235 ...... If it EVER goes much over the middle -- do not continue to drive the car .... if it overheats you can warp the head.


Make sure you find where the coolant is going -- you do not want a hose to blow and have the engine overheat. This year has the defective water pump and the plastic thermostat cover. I would think with the miles the WP has been changed. Check the thermostat cover. If the level is Ok and does not drop -- it could be the sender in the tank -- the sender is an easy fix. You don't want to have any coolant problems with the Jaguar V8's

The ABS pump has a known failure point in the control - the solder fails - do a search and you will find a lot of information.


Also ....whenever you have a flashing CEL (on any make) -- this is telling you that the computer is detecting a misfire great enough that unburned gas may be exiting the engine and flowing into the catalytic converters. The unburned gas will ignite in the converters causing them to overhead and melt - not good.

 

hahaha I can tell you almost every solution.

I've had all of these problems.

1.Since the cover is off, Do a quick tune up. Plugs are cheap and Fix alot. My recommendations are Branded NGK. But if on a budget. Look for anything that is platinum or double platinum or iridium.

2. Go under the car and see if the radiator is pushed back. Mines was a few times and causing coolant to spill out the overflow tank. (wasting my money)

3. Restricted performance. Can be from a few things (Cylinder Misfire, or Coolant)
Advice. Replace all the plugs cant be more than $30 for 8, 1 per cylinder. Next replace the coolant temperature sensor, get a new one not off ebay. a good parts site is partsgeek.com about $18.00. (that was my reason for restricted performance.

4. ABS, Traction Control Fail, Stability Control Fail. Are all one code. You wont find them with no code reader. Its little Sodder points in the abs computer that have came loose and you can fix it yourself or have it fixed for about $50. Search ABS repair on ebay for xj8 (which your year) should find a few services you just remove the computer and ship it to them, and those codes go away.

5. OPTIONAL. Since you have high mileage. Last thing you want are engine or transmission problems. Do a quick transmission flush. Most shops charge $150 for this. For the engine do a engine flush. Pure some liqui moly $10 amazon. engine flush in there, and let the engine run for a while (15mins) and do a oil change it cleans the sluge out. **** really works. Helps you live a little longer on this car. (Use regular oil for the oil change, maybe castrol high mileage formula, i think 5w30, and if you have an oil leak go up to 10w30.) dont spend for sythenic when this car allows regular.

Another thing dont put cheap gas in this car it says 93 premium only. put that. unless you wanna buy knock sensors too. about $200 each and you need 2 lol


And when you post codes post what they are. lol I dont feel like looking them up.

If you need any help let me know. I know this car like the back of my hand.

I dont know whats the inspections guidelines in your state. But you should check the brakes and balljoints and tires for safety.

 

another thing, goto advance auto parts or auto zone and get a pack of claps for the radiator, swap them all out they arent more than 6 dollars for everything. i was driving on day and a hose flew off and i was screwed. didnt have any coolant on me, and i couldnt find the clamp.

once all thats done, buy a coolant pressure pump. it screws on to the fill tank for coolant and you pump it, and shows if you have any leaks in your system.

another recommend thing is do a radiator flush. theres a drain plug on the drivers side bottom edge of the radiator you can screw off and drain all the juice from.

I dont know what kind of person you are. but i rather knock all the common problems out before they get serious.

if your like me, buy K&N Head gasket repair (green bottle looks like a mini nos tank), run it directly to the radiator and it will fix any problems before they worsen. after you use it as directed drain it from the system and fill the radiator with coolant 2 extended life, and 1 50/50 mix.

Im just trying to give you as many quick fixes to knock out. that are all under 100 dollars combined.

you can save alot doing this all your self rather than paying for labor. if you need help or directions. I can try to guide you as detailed as i can.

 

Thank you everyone for your replies, here's what I've done so far:

I got another coil pack to replace the errant one, and I also replaced the spark plugs. The car runs a lot better and it hasn't thrown a code since.

I am now looking into replacing the chain tensioners, since everything I have read on here indicates that they can fail without warning and catastrophically. I've seen kits on ebay that include the chains as well, and that's the route I'm probably going to go with, since it's better to be safe than sorry. I'm also going to replace the water pump, since I'll have the front of the engine apart anyway. I've seen some really in-depth info on here about doing this and I'll probably open up another thread if (no, when) I have questions when I start to do this.