Hey guys . So I have had my 2011 xj for about 3 years now . And it’s been a roller coaster. So the fuel system I’m completely new , and it has no codes . But since I bought this cat with about 87 on the clock (it now has 117,500) it has had a very consistent vibration at idle or at speed . It’s like a surge & vibration . And it consistently changes with rpm & gear if I’m driving…..

for example at idle if rev it at 1k rpm it actually misfires and sputters at about 1250 rpm the vibration can be felt in my seat -

at about 1750 I can feel it more in the floor & gas pedal & steering wheel . Consistently and as the rpm’s increase , the vibration gets faster in the time that it returns as if it’s rotating with something. Alll my bushings / mounts / everything that can transmit a vibration is new . And it has not changed the characters of this vibration . I’m lost as to what it can be . It’s been 3 years and it’s slowly but surely getting a littlllleeee more noticeable. I’m thinking it could be the guides wearing down but I’m not sure . I do not hear the clatter associated with that . And looking through the oil cap the engine looks absolutely spotless. Literally looks brand new . The howl that I can hear inside the vehicle sounds to be coming from the center console . No fluid changes has changed that either ………. Please someone help !

 

I really don't know what it could be but it don't sound good are any codes present , you should get it booked in to a good Indy . Good luck

 

Post what your using to read codes. It's probably not good enough to see what you need.
If you have miss-fires it will set codes.
Do you have P1111 or P1000? You must have one or the other of these as they related to emissions testing.

Do you know what SDD is? You might need to get the car hooked up to one of those factory diagnostic systems to find out what's going on.

Have both engine mounts AND the transmission mount been replaced?
Please post ALL the individual parts that have been changed. We need full information to help.

The car is over 100K miles have you replaced the spark plugs yet?
Your also past a transmission fluid/filter servicing range. Has that been done? Was the fluid level set correctly when the transmission fluid was changed? I think you have serviced the transmission?
What fluid did you use?
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hey , car has 0 codes , yes spark plugs have been done , & I have the trans fluid done every 15k miles . Ik it’s over kill but I drive the car very hard . All the mounts have been done . All the injectors, and high pressure pumps . The problem that I’m having persisted before and after all these changes . They didn’t change the characteristics of the problem I’m having one bit ….:. If I’m driving and get the car @1000 rpm it does NOT miss or sputter …. Only at idle it does the little sputter and miss . I’ve held it at the rpm to see if it would throw a code . And it doesn’t even after several minutes….. no vacuum leaks have been found either . I’m believing it could be something related to the torque converter but I’m not sure . I’ve heard something about that being a cause . And timing guides maybe . But like I said no clatter .

 

Great work on all the maintenance! I must say 15K to change tranny fluid will keep it nice and fresh!
But what device are you using to get codes?
It's very common that IF your not using SDD the car won't show any codes.
Until you can use something with the capabilities of SDD I think we are not seeing what's going on?

Good point on the TQ as the earlier 6 speed ZF's occasionally had the TQ clutch act up and cause severe drag on the engine. Sometimes even causing the engine to die at idle due to the extra load from the TQ/transmission.
But again this sets codes?
Here is a TSB on the TQ but it only points to the earlier S-Type so maybe it was fixed in the later years?
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. Hey so I just have a regular scanner , nothing fancy . But it does pull abs / electrical fault & codes of that nature .I have a video of how the car sounds at idle . I couldn’t up load any longer of a video . But I’m aware the injectors are loud . And also the intake makes sounds as well . But this kinda sounds like it’s slapping now that I think about it . But it doesn’t always sound like that … but it does more then it doesn’t . And that sound does match the vibrations I feel in the cabin ( not perfectly) but does seem to be related