Hello everyone. I'm a fairly new to this site and would like to express how useful this site is.

I've spent many hours on this site reserching everything about owning a 2003 STS with 130,360mi. I bought the car knowing it needed service and repairs. I serviced and/or replced the following...tranny fluid and pan along with sleeve.

I did spark plugs, air filter, fuel filter, pcv valve, both sets of intake gaskets, valve cover gaskets and knock sensor.

When I first got the car it ran poorly. The CEL and resrticted performance/gearbox fault indacters were on. Major improvements were felt after doing work and clearing all DTC's.

Currently the only DTC I'm having an issue with is the knock sensor P0328 and random restricted performance. I already replaced sensor with new one. I tested the voltage at the harness with my DMM and read 4.95v.
Not sure if that is normal.

Can anyone confirm? Anyone have any input? I know I can solve issue with the help of this forum. Your help will be appreciated.

 

A few problems??
I don't know what a STS is?
I don't know what engine you have?
Did you change the correct sensor? The V-8's have two knock sensors.
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.
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My car is a 2003 S Type Sport 3.0. Has knock sensor on top of engine.

 

If you changed out the knock sensor - perform a hard reset of the ECU or take your OBDII scanner and clear the code(s) - you should be set...

 

I did clear the code after I replaced the knock sensor, but it came back. I was thinking the knock sensor I installed is defective. Is there a way to test the knock sensor with my DMM?

 

Update!

I went back and disassembled the intake and fuel rail to get access to knock sensor.

I removed it and found it dirty and oily where it makes contact with the engine block.

I cleaned both the sensor and surface of the block to make a clean contact and torqued it down. I made sure the knock sensor harness was not pinched or damaged. All good there.

I then decided to check the spark plugs for proper gap. To my surprise the gap not set right. I assumed the gap was already set and didn't even bother to check when I replced them recently.

Note to self...remember to check the gap on spark plugs.

I gapped all the plugs to spec, assembled everything back together and thought that I solved my issue. Wrong gap on plugs causing pinging setting off the knock sensor. Makes sense to me.

So I start the car and clear the DTC hoping that I fixed my knock sensor issue.

After a short drive the CEL came on and the PO328 DTC was back. Very fustrating but I got a break. This morning the CEL indacter was off. I did get restricted performance on and off, but no CEL. Keeping my fingures crossed.

 

Not pre-gapped correctly... which plugs exactly?

 

I put in Bosch Platnium, but I'm swapping them out for oe plugs. Car had Motorcarft SP-459 plugs originally. Even though the MC SP-459 plug is labled platinum, it's center electrode is irridium alloy. I'm hoping that once I swap spark m knocjk sensor isuue will be solved. Getting them later today so I'll do the swap tonight and update results soon.

 

Hope to hear........

 

Swapping spark plugs didn't solve issue. I found some useful information from this site http://www.wellsve.com/sft503/counterp_v4_i4_2000.pdf. All I can do at this point is do more troubleshooting. I did dump almost a full pint of Sea Foam last night into gas tank. Only noticeable diffrence so far is car is out of resrticted performance more often than before. This car is so much more fun to drive when it's out of restricted performance mode. That is why I want to fix this knock sensor issue so bad. In the mean time I'll keep at this and post results.

 

Another useful link, it has spark plug and car fluid specifications for many Jaguar models Spark Plug Specification 17 for 2004 Jaguar XJ Vehicle Specifications

 

When was the fuel filter last changed?

 

The proper specs are all on this site. Seafoam sounds unwise, to be kind.

 

Fuel filter replaced within last month. I've used seafoam before with no issues on other engines. It was on sale so I thought maybe somehow this will fix or help me fix my issue.

 

Double check to ensure the arrow on the fuel filter is pointed in the right direction. (Towards the fuel line going to the engine) - This is missed very easily.

 

I checked and all is good with fuel filter position. But I did read and look into another cause for the knock sensor issue. I suspect a faulty fuel injector. I was listening for any noise that seemed out of place in engine compartment. I heard this ticking or clicking noise to best describe coming from the fuel rail. I moved around and evaluated all options and have no doubt that noise is coming from fuel injectors. To eliminate some doubt I held a screw driver up against each fuel injector and most definately noticed a difference. Two of the six injectors had noticeable vibration. The other four felt silent compared to the other two. I'm doing resistance test on each injector today or tomorrow. I'll post results soon.

 

Tapping sound at the injector is normal - check the electrical connections at each injector and ensure they are on tight and snug. Resistance testing should yield some results but make sure those electrical connectors are placed back on snug and take your time disconnecting those locking tabs.