Hey guys. So I bought a 2002 XJ Sport and I absolutely love the car. It's like nothing I've ever driven before. (It was the silver one from my other thread, I'm sure some of you may remember).

Anyway, here's what happened and now I have an intermittent Restricted Performance warning and now a CEL on.

This is in chronological order:

I bought the car friday, drove it home and drove it around no problems.

Saturday, I drive the car from Central Jersey to DC. Not a problem to report.

Same day, on my way back, I go to overtake somebody and give it the beans, all of a sudden acceleration stutters heavily and the HUD says Restricted Performance. I let go of the gas and coast (while at highway speed). Says it for like 15-30 seconds but then goes away. So I'm like...ok interesting. Never happened again until next event. Acceleration was fine and was able to drive normally.

Next, I pull over for food. All is well now. As we leave the food establishment I get back on the highway. All is fine until I do another passing maneuver. Restricted Performance again, and CEL finally comes on. But the RP notice only stays on for 15-30 or so seconds as I let the car coast at highway speed. It then goes away but the CEL stays on.

I drive the remaining 150 miles back to NJ and it never comes on again. I'm able to drive normally, and go WOT without issue etc.

Same day, I drive to NYC for a family gathering. All is well for the 30 mile trip.

On my way home, I get RP more often. Except this time, it only happens at city speeds and ONLY after I start up the engine, and it was only warm starts. I have yet to try cold starts and see what happens. But again, it will come on I'll be able to accelerate normally to city speeds, and I'll be light on the gas, and it will go away after 15-30 seconds.

It happened every time I turned off the car and started it up. And once it will go away, I'll be able to drive normally because I drove home without issue and had no RP notice while on the highway.

What do you guys think it could be? How would I go about diagnosing this? Also, I've never had a car this modern (keep in mind my most modern car was a 1994, and it didn't have OBD or anything) so how would I get the codes read? Does it cost $ just to have codes read?

I did some searching and found that it could possibly be a faulty knock sensor or a vacuum leak. What say ye?

Thanks in advace

 

The only way to know for sure is to pull the codes. Anyone with an OBDII Scanner can do it. Usually your local Autozone or other parts store will read the codes for you for no charge.

Take a piece of paper and a pen and write them down. Run a quick search of the P0XXX code here on this forum and you should get a hit. If not repost with the code(s) and someone will answer.

Don't freak if you get a whole bunch of different codes. The whole system isn't likely failing but one issue can cause other temporary problems down the line.

I'd recommend that you purchase a code reader and keep it handy. I spent $85.00 on mine and it's saved me trips to the parts store. Plus you can clear fault codes that are stored in the ECM that way you have a fresh slate to work from when repairs are complete. Many of the parts stores say they are not allowed to clear the memory for one reason or another.

Keep us posted.

Ken

 

Alright. So I got a code reading at Pep BOys and today, the CEL seemed to extinguish.

Codes I got:
P0328 which from searching is the knock sensor like I thought.
And P1111, which indicates all is well in any other case.

This place is awesome!

I'll be getting around to fixing the knock sensor hopefully this weekend.

Where is it located and is there a DIY?

Also, which one should I buy?

http://www.autopartswarehouse.com/se...=knock&submit=

 

Check out this thread and in post #6 there's a part number and supplier called out. It's a lot cheaper than the Dealer part was for me.

https://www.jaguarforums.com/forum/s...ad.php?t=43922

As far as ease of replacement it's a piece of cake. All you'll need is a magnet on an extension wand, a 13 mm deepwell socket, a ratchet and a long extension.

Yours is on the passenger side (Bank 1). It's down below the intake manifold (near the center) but you can get at it between the runners.

1. Undo the electrical connector at the water outlet/t-stat housing.
2. Remove the 13 mm nut that holds the sensor and if it drops out of the socket get it with the magnet. (A dab of grease in the socket usually prevents the nut
from dropping)
3. Next use the magnet to grab the compression limiter barrel in the center of the sensor and lift it off the stud.
4. Reverse the process for install.

Good luck. Ken

 

Make sure to check for cause before replacing - the chart has four possible causes for P0328 -



Chart is attached below.