My 2006 XJR has been sitting for 4 months

Prior it was on the Road driving completely fine.

Until I started having problems with acceleration The vehicle started to buck

Every Cylinder had Misfired.. I had a Jaguar Mechanic Look at it he told me it was the lifters(The Jag Mechanic Kept Telling me to buy a engine so he could put it in -(He was trying to make a couple bucks on the side he came off odd anyway).. I had four other mechanics look at it and they said it was the supercharger..

No offense to Jaguar Mechanics I can only speak about the one who told me it was the lifters

The vehicle has a Problem driving up hill when it reaches 3K RPM It Hesitates

I had changed the oil Religiously I don't believe its a lifter

I put a Flat head screw driver to the supercharger and listened from the head of it , I heard a loud scouring noise ..

Does anyone know what it can be?? Even though I had four mechanics look at it. I just would see anyone's opinion on what they think.. I found a Supercharger and I am going to purchase it. I just want to be sure its the supercharger.

 

My 2006 XJR has been sitting for 4 months

Prior it was on the Road driving completely fine.

Until I started having problems with acceleration The vehicle started to buck

Every Cylinder had Misfired.. I had a Jaguar Mechanic Look at it he told me it was the lifters(The Jag Mechanic Kept Telling me to buy a engine so he could put it in -(He was trying to make a couple bucks on the side he came off odd anyway).. I had four other mechanics look at it and they said it was the supercharger..

No offense to Jaguar Mechanics I can only speak about the one who told me it was the lifters

The vehicle has a Problem driving up hill when it reaches 3K RPM It Hesitates

I had changed the oil Religiously I don't believe its a lifter

I put a Flat head screw driver to the supercharger and listened from the head of it , I heard a loud scouring noise ..

Does anyone know what it can be?? Even though I had four mechanics look at it. I just would see anyone's opinion on what they think.. I found a Supercharger and I am going to purchase it. I just want to be sure its the supercharger.

 

Run the codes on it. It sounds like an ignition issue if their are misfires on every cylinder. Problems like these generally aren't a big deal but can be hard to diagnose. To me it sounds like a fuel metering issue where the engine is running too rich or an ignition issue.

The blower is always going to sound funky with stethoscope attached to it. What you want is a consistent sound. Rattling is what you're trying to avoid or any inconsistencies.

 

Supercharger may have gone bad (bearings/coupler), and that will cause loud noises, so must be repaired. However I can't see a relation to the hesitations/misfires, even if the sc would operate less efficient. Would ask the 4 mechanics why they think there is a relation...

 

If the car runs okay until 3000 rpm, it is being perfromance inhibited by the ECM, it is probably not the supercharger. As was said, read the computer codes, there will be something there if it is in inhibited performance mode. Many things can cause the car to cut out at 3000 rpm, low transmission fluid, a transmission problem, a bad knock sensor, anything that the computer is programmed to protect the car against.

 

Yeah, the couplers get noisy and mostly at idle. You may have a bypass solenois sticking open for the super charger and its not gonna build boost. But otherwise i think to need more checks like, fuel pressure and any retained codes that would bive morre info...if the secondary fuel pump is inop you will get poor pefroamnce at 3k and up. The car runs fine on the primary until you hit boost then the secondary kicks in. You also may have an internal line in the fuel tank thats cracked or disconnected doing the same thing. Ive seen alot of this on the later xj's. But be forewarned, if that is the issue the rear electronic control module adjust the pulse width of the fuel pump drivers to maintain the somewhat correct pressure. And when you fix an issue the module has "learned" what is has to do to keep the car running properly or at least running. Then you end up with pumps being overdriven and engine problems. Its a long term learn and won't relearn quick enough to change. You must eaither try a hard battery/cer reset, or if that doesnt do it, youll have to go to the dealer and have the rear electronic module reprogrammed.......arent computers great

 

When the Xjr first starts up it will drive until 1 or 2 minutes later then it starts to buck and hesitates it will also shut off on hills .

I have to keep featuring the gas pedal just to keep it from bucking..

Driving down hill and using the inertia wasn't a problem driving when trying
to get it back home but when I got to A HILL THE SPEED WOULD DROP TO 15 WHEN THE SPEED LIMIT WAS 35MPH

Coming up the hill to my house it will go into "Restricted Performance"

It did have a Thermostat code thrown at my last vehicle check I haven't had it repaired.

Now Im paying the price guys

Does this help to more to pen point what is going on with it?

 

When the Xjr first starts up it will drive until 1 or 2 minutes later then it starts to buck and hesitates it will also shut off on hills .

I have to keep featuring the gas pedal just to keep it from bucking..

Driving down hill and using the inertia wasn't a problem driving when trying
to get it back home but when I got to A HILL THE SPEED WOULD DROP TO 15 WHEN THE SPEED LIMIT WAS 35MPH

Coming up the hill to my house it will go into "Restricted Performance"

It did have a Thermostat code thrown at my last vehicle check I haven't had it repaired.

Now Im paying the price guys

Does this help to more to pen point what is going on with it?

 

ids still look to fuel pressure, but the bucking and RP can also because caused by a bad mass air flow sensor, and by bad misfires from coils. I keep a few MAFS in my tool box wether theyre correct or not and swap them in if I suspect it. Im looking for a change in operation to isolate this, and after all its only 2 screw and 30 seconds to swap. But you really need a good diag, because Im just telling you what I would look into first, not what it is. But I always try to go to most likely and most common issue first. Looking into something like a bad SC I wouldnt even consider because Ive replace 1 in 14 years and they dont exactly "FAIL" but get noisy at idle. And yes get the t stat replaced because if the engine is too cold, (I know you have a p0128, temp below threashold) it runs rich, and this can lead to plug fouling and poor performance. But thats a streach, well its a streach in Texas where its not that cold, but not in Pa. this time of yr(this is why we always ask on here for owners to provide location, yr model and engine) the t stat has a rubber seal that tears and holds the stat open. Better that than the 4.0 t stat, they tended to stick closed, I would rather run cold than overheat anyday
Hope this helps

 

Im taking my vehicle to a garage called Barnes Automotive they specialize in Jags for diagnosis. I appreciate everyone replies and "Brutal" if lived in Texas I would bring the car to you. Thanks Again

 

I suspect it isn't the problem but have you checked that both fuel pumps are working? (the XJR has two)

The X350 training guide says:

On S/C vehicles with twin pumps, they are fed by two separate fuses F24 and F33 in the rear power distribution box.

If either pump fails to work and the tank is below half full the operating pump will transfer fuel to the other side of the tank, (faster than it can deliver the fuel) causing the vehicle to stop running. If the tank is above half full the vehicle will continue to run but will not make full power. The fuel gauge will drop to zero and there will be a reduced power message.

 

HMM interesting...

When I Fill the car up it seem to run better but it would buck but not as much...

I use to drive the vehicle down to 20 miles left in the tank guys

My mechanic always told me to keep above a quarter tank..

Once I drove to the gas station on zero miles on the tank.

Maybe I damaged the fuel system that way..

Im paying the price

 

merged BOTH of your threads, asking the same thing. Please note, no duplicate posts, whether in the same sub-section, or on multiple areas of the forum. thx!

 

If it runs fine for the first minute or two, then it isn't anything like the supercharger. What's happening is that after a couple of minutes the car warms up and the ECU goes into "closed loop." Whatever is happening is something that the computer is sensing and trying to compensate for. I had a problem in my old Series III where it would start to hesitate and run rich at the same spot on my way to work in the morning, a couple of miles from my house. I hooked up a laptop and watched it and as soon as it went to closed loop the fuel trim went full rich. A new O2 sensor fixed it.

 

+1 on the secondary fuel pump, especially with the added factor of power loss going uphill.

 

I dont know what I was thinking(actually I glazed over 06 xj) when I said 2 pumps. A 06 DOES NOT have 2 pumps like the earlier 2003 and priors. I has a electric primary pump, and a mechanical JET pump that only transferes fual across the tank to keep even levels between the 2 sides since it is a saddle tank over the driveshaft. Unlike the previous tank that was behind the back seat in the trunk and no jet pump but 2 electric on the SC engines.
Now for yours if you have not checked I would pull the capo on the passenger side of the tank and make sure there are not any cracked or loose plastic lines.
Sorry about the foopah on info, 1 of the hazards of answering questions concerning any yr and model of jag

 

Could it possibly be blocked or bad catalytic converters? I had the same problem on one of my cars, it would almost die on a hill, the converters were plugged up.

 

I think the key here is that it runs fine for the first couple of minutes, when its in open loop. Once it goes to closed loop and the ecu starts adjusting things based on sensor readings something happens. That would leave out things that would always affect the engine, like the supercharger or
the cats.