Hi, I just bought a 2006 xk8. It has 60k miles was garage kept and is in generally good condition. When I purchased it the mechanic said there was nothing seriously wrong with it except some wear on the bushings and electric seat faults. Since driving it for a few weeks the amber dsc/abs warning light came on but I cleaned the sensors and it stopped coming on. My issue is this, the whole time it doesn't seem to want to move. If I take my foot off the gas at a stop sign it sort of barely moves forward. Like it's still being braked. All cars I've ever driven including my 98 XK8 have a little pop to them and start to move without the gas. If i put it in reverse and dont give it gas it rolls off right away. When I do give it gas in drive it kind of half assedly moves unless I agressively accelerate. There's also a slight jump from first to second gear and possibly just in general (as in when it's not shifting) it's not a serious jump but one you can slightly feel. Also when driving slow or rolling without pressing gas (as in in traffic) any minor touch of the brake will slam the car to a stop, they seem to seize on. At high speeds it moves but it still feels heavy like it doesn't want to go unless I'm aggressively accelerating. If I take my foot off the gas it instantly loses significant speed, it doesn't seem to coast or roll off of momentum without depressing the gas. I thought it might be the transmission but it's not blowing any codes or leaking. I don't want to spend $1000 on transmission work if it's something else. Could it be a brake issue? The car was garaged for 6 months before I bought it. Anybody have any ideas? I'm getting out accelerated by volkswagens.

Thanks

 

Could it be a binding brake ? take it for a good drive and check the temperature of the wheels . park on a slight incline and check the car rolls forward when in neutral.

 

Your accelerator cable may just need to be tightened. There are instructions here on the forum on how to do this. Type "XK8 accelerator cable adjustment" into the search function, read up on the process, and give it a try. Most owners affected by this issue are amazed at how much quickness returns once they tighten the slack out of their cable assembly....

 

I second this....I did that on mine 2 months ago..the result is as if the car 50hp more...do it!

 

Make sure they're not a turbo or 'sport' version before deciding to show it who's boss

 

Thanks all,
David, How do I check the temperature of the wheels? They're all warm but they've also been on the road for awhile so isn't that normal? The car rolls in neutral but im not sure if its rolling as well as it should. In drive without gas it only goes about 1-2 MPH and still feels like its trying to stop. Any sort of slight upward incline will stop it unless i press the gas.

Jon/ZidJan
I adjusted the throttle cable. I initially moved it too far. The car jumped when i touched the gas, but the issues continued (just faster), i adjusted it down a bit so the throttle is responsive and it definitely helped with power. But it still feels like somethings holding it back. I think its either the brakes or Transmission. I cant tell which because neither are showing obvious problems. There's no brake noise or smell, and the transmission isn't leaking or blowing codes. There is a slight pull to the left but i think it just needs an alignment.

To summarize the issue a little more:
1. Car doesn't roll forward when in drive (with no gas), barely moves.
2. When accelerating through 1st and 2nd gear it tends to shift weird, it sometimes almost skips first completely and goes straight through to second (with a jump).
3. When decelerating at normal speeds and then attempting to re-accelerate, I have to press the gas relatively hard and then it will jerk when shifting back up (not sure if this changed with the throttle adjustment). It also made a terrible noise the other day when i braked from 85 to 60 and then tried to press the gas, but that's the only time I've heard it.
4. The brakes jump on with very little pressure, and they seize immediately at low speeds, jerking the car to a stop
5. Car slows down very quickly as soon as the gas is released, doesn't glide at all.

It feels like either the brakes are on slightly, or the transmission isn't tuned quite right. It doesnt feel like a transmission fault because its not blowing codes and does manage to shift alright a lot of the time.

My mechanic doesnt seem to have any idea.

 

Well, it seems like it has to be something with either the brakes, the transmission or an odd chance on being some wheel bearings that are not working properly.

It might even be something with the traction control system that is applying the brakes when it should not be. You should get up to a decent speed and then put it in neutral to see if it decelerates quickly as you say that it does when it is in gear. If it doesn't, then it should not be a problem with the brakes. If it does, then you should disable the traction control system and try it again and that should tell you if it has anything to do with the brakes or traction control system or even any bearings. Anytime you have some sort of problem that you can't figure out, it is best to just try to start eliminating things that it could be. If the deceleration is not being caused by the brakes hanging up or the traction control system then it must be something in the transmission. One other test you could do is to get the wheels off of the ground and put the car in neutral and then try to spin the tires to see if any of them are overly difficult to spin. You have just got to do everything you can think of to eliminate what it could be and at the end you should be able to identify what it is that is causing the problem. Let us know how it works out.

 

Tried that. Neutral seems to work fine, doesn't slow the car more than it normally would. When I'm gliding to a stop (without the brakes) it glides much further in neutral than in drive.

Also 1st gear seems to Rev a bit before slightly jerking into 2nd

 

Well then, it is not likely to have anything to do with the brakes or the traction system so it must be the transmission, even though it is not throwing codes. I can't think of anything else that could be causing the symptoms you are reporting, but then, I am not an expert mechanic, as some members on this forum actually are. If they have an alternate idea, perhaps they will share it and then you can go from there. I hope you can find the solution right away.

 

Could a valve body issue?

 

I would turn off traction control/abs to be sure that isn't interfering, particulary as you had a fault. If that doesn't help, my thought would be to have the TCU reflashed now that we know it rolls fine in neutral and reverse. Reflash should help the harsh 1-2 upshift too. Oh btw, I think there was another member experiencing the same issue recently...unless that was you as well. Do a search to find that one and see if there was any resolution.

 

Another couple things to try:

I remember a LONG thread a while back about someone describing the same general feel from the car. I believe part of the discussion was that the tranny just works that way, and that some form of resolution was obtained by doing the "hard reset" procedure at the battery.

Also, have you tried the "sport" mode? The car seems a lot more responsive in sport mode. Just for a data point, I guess it would solve nothing.

Beyond that, I assume you have covered the basics like using premium gas, adjusting tire pressure, etc. I assume using regular gas will cause pinging, and the knock sensors will tell the computer to dial back the ignition timing, leading to a more sluggish engine feel. Also, do not neglect the brake switch, as it is a key input into the transmission shifting strategies (do you have "cruise not available, check rear lights" ?).

PS: have you checked for leaks at the transmission? fluid level is a key factor, here. Possible leaks are at the (plastic) pan, at the electrical connector and at the output flange. A word from Captain Obvious: if there is a leak, the fluid is low.

Best of luck, keep us posted.

 

Here is the thread fmertz remembered. Dealing with Lucy and Ethel every day apparently hasn't hurt his memory. This owner had similar symptoms, and resolved the issue with a hard reset.

https://www.jaguarforums.com/forum/x...-coast-128679/

 

Thanks all, ill look into these things.

Couple new developments. I mentioned earlier that i cleaned the DSC/ABS sensors and the light went away. It was like that for a week or so but now its back. it shows up around 1/3 of the times i drive and becoming more common. Usually right as soon as i move. I didn't clean the little gears, just the sensors themselves, i don't know if that would make a difference?

Also the shifting issue is become far more noticeable. Gear 1 will rev up and then lurch into second. after that it seems fine unless I'm downshifting and then up-shifting in which case it seems to slip.

thoughts? is it all one thing? or multiple problems?

Sam

 

Couple other notes:

I'm using premium gas
Only getting the DSC warning light
No Transmission leaks although it does seem to be dripping a considerable amount of water from what i assume is AC condensation (Socal is warm)
Initially turning of traction control seemed to solve the problem (although now it shuts itself off with the warning light and the problem persists), also now the shift issue between 1st and second is significantly noticeable.

The engine braking issue sounds like its just trained to drive with the old guy i bought it from, ill do the hard reset and see if it fixes it. I'm still getting the shift issues and DSC warning lights however.

I read on one of these threads that I should flush the DSC/ABS sensors and the little gears they read with brake cleaner, i didnt do that, just washed the sensors with water. The rear sensors were considerably dirty (and so were the gears which i didnt clean) and the problem went away for awhile. Would the gears being dirty be enough to throw the sensors off and cause the DSC light? I'm assuming thats my next step? Would that impact transmission shift at all?

 

Having owned this car for only a few months and catching up on repairs, it sometimes feels like the famous factory scene.

 

I would definitely focus on the traction control codes first. Re-check the sensors, clean the "gear" ring, check and re-check the plugs AND wires at each of the sensor ends (breaks in the wire have been known to occur). Also, while there, consider flushing and bleeding the brake fluid. Air pockets in the calipers cannot possibly help this situation. I understand the computer has codes specific to each corner of the car, so if you have a reader and if at all possible, swap parts/wires from side to side, and see if the code follows the part swap.

The reason I am saying this is that these are near zero dollar homework-type activities you can do before throwing money at the problem.

 

OMG....I am having similar issue with you right now..only mine is throwing off transmission fault also... which I believe is caused by the ABS light, wheel speed signal fault