Hi guys I have a 2007 Jaguar XK I have owned almost a year now. Today I was accelerating on
the freeway and the the car key accelerating holding at 5,000 rpm I was slamming the brakes
and soon after about 30 seconds it went back to normal driving. This is the 2nd time this has happened
once it happened when i was turning on the road and started to accelerate fast when the same thing
happened. I called the local dealer they said to bring in and they think its a throttle sensor.
Has anyone else experienced this?

 

This brings up a secondary question. With Lexus if you have a run away engine if you press and hold the start button for 3-5 seconds it will shut off the engine but allow you to steer and brake. Does anyone know if Jag will be doing the same.
As for the OP problem I have not had or heard of this problem.

 

Just make sure that when you were slamming on the brakes you didn't inadvertently press the gas pedal at the same time. That can happen if the ball of your right foot presses the right corner of the brake pedal, instead of the center of the pedal, and you don't realize that your heel is also pressing the gas pedal.

Back in the day, racing drivers with manual transmissions intentionally used that "heel and toe" technique to simultaneously downshift and brake into corners. See: https://www.caranddriver.com/feature...o-heel-and-toe

 

Welcome to the forum Smartcat,

I had a 2007 4.2 for four years and never experienced that issue.

Acceleration control on the 4.2 engine is by an electronic throttle drive-by-wire system. The throttle is connected electronically to the ECM. The ECM then controls the fueling for the relevant throttle demand signal from the APP sensor on the throttle pedal.

Provided the throttle pedal didn't simply stick, there has been an out-of-range signal occurence from the APP sensor. This should have set a DTC (Diagnostic Trouble Code) which will identify the cause.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some information about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

Yes... I have tested it in my '11 XK.

 

I will be taking my car to the Jaguar Dealer this morning I will keep everyone posted .Nice to learn more about the Start switch
button to shut off the engine, will have to see if applies to my year model.

 

The two most likely things, are something jammed in your foot well, or you are hitting both gas and brake.

When I first got my XK, I put in my floor mats from my 944, when the throttle depressed, it could get wedged with the lining of the floor mat, this would hold the throttle down when I released. I could take my foot back and not be on brake or gas when this happened, with an accelerating car.

Solution, brake it back free to shut throttle.

Although normally I'd say when this question comes up that you were on both gas and brake; it sounds to me like a physical object got jammed, in both cases you were accelerating, lifted off, and kept experiencing acceleration.

I've found all the run away acceleration questions I have seen on this forum up till now to be when trying to slow the car down, not when trying to accelerate. If the engine gets gunned when a driver is reaching for the brake pedal, they probably also hit the gas, then when trying to go deeper on the brake pedal to hold, got deeper on the gas, etc... This doesn't seem like your scenario. Instead it seems like mine.

 

Brakes should always stop the car.

I can't see it being a throttle issue as there are 2 (different) sensors and if they disagree the car goes into one of its restricted/limp modes (with dash message). No way will it accelerate as described.

There are also 2 sensors on the accel pedal so it also wasn't the cause unless pressed down for some reason (floor mat or the driver).

Now, a sudden vacuum leak that makes the car add fuel just about could be it... maybe? Would pretty much have to be a joint or hose that flexed so the problem appeared and vanished.

Nice typo BTW - had me wondering who was doing what on an airfield!

 

Well Everyone it was Aftermarket Floor mats that were sticking to my pedal.
Everything else is great on my car. I love my Jaguar XK and hope to enjoy driving
it a few more years .

 

Phew! Scary but could've been much worse.

 

Your symptoms and causation matched my own experience with 944 floor mats in the XK.

Everyone else that has had unintended acceleration I'm pretty sure has been from foot on gas and brake without knowing it.

Were you able to get Jaguar XK specific mats?

 

I have to pick my car up from the dealer and will check out Xk mats. It rains a lot here so i will have to invest in some
mat that won't take me for a wild ride again

 

That Acceleration Problem from ..... fifteen??? years ago with I think Toyotas???? was undoubtedly all two-pedal pushes or floor mats, although....... oh heck, my brain doesn't work any more. Didn't Toyota get fines or did recalls or something???

 

It was Lexus when you install a floor mat over the OEM mats the gas peddle would stick. Family got killed with this and Lexus was sued. The lexus fix was to cut a 1/2 inch off the bottom of the gas peddle and send out a warning to owners telling them to remove OEM mats if they are installing another mat. Seems people don't know not to install a second set of mats without removing the OEM ones. Seems to be a common problem when people put Weathertech mats over their carpet mats.

 

Lexus = Toyota, so I was half right.

 

In cold locales the extra floor mat can make a world of difference in keeping the floor warm. That said, I do not double up on the floor mats. Use the seasonal one and that's it.

 

I picked up my car today . The goodyear rubber mats can be trimmed by the accelerator pedal so they don get caught again.

 

Thanks for posting the outcome.

I've added 'RESOLVED' to your thread title.

Graham