Anybody have this occur, it's happened twice now.

Both times a couple minutes after start up and both times after stopping under normal conditions from slow drive to a stop. Engine surges as if under full throttle even though my foot is on the brake, all I can do is just press on the brake as hard as possible. The brakes override the power, but still, not a very nice experience and the brake effort is significant. I keep it on sport mode most of the time, not that it should matter. Throwing into neutral from sport is a bit tricky in a panic w/o it going to reverse. Hope it didn't damage the gearbox, so far so good.

First time it was at a crosswalk, thank God the person had crossed, even so she gave me quiet the evil eye until I explained.

Second was last week at an intersection going onto a sort of busy two lane. Car wanted to jump in front of a big fat truck.

 

Regardless of how hard you push the brake, a part of your foot is touching the accelerator pedal.
This has been discussed MANY times. MANY MANY times. There is no way for the engine to rev without pressure on the accelerator pedal.
Maybe the mat worked its way up and did something bad. Maybe you have large feet and an edge of the sole caught an edge.
I've done this myself and it was always my big ole foot pushing down on the Fun Pedal.

 

Yea, saw that thread after I did a search with no results until after I posted what I thought was a new topic.

In both of my occurrences I came to a stop, had been stopped for a few seconds already, so my foot was not the culprit.

The acceleration occurred sometime after I stopped the car and it was sitting at idle the first time about 5 seconds the second closer to 10-15 maybe even 20 seconds as I waited at the stop sign for traffic to clear, if my foot had been on both pedals the acceleration of the engine would have been simultaneous to the brake foot pedal. I'm a little guy with a little foot, [ but disproportionate on the other....so I've been told.... ;-) ] I can drive the Europa with size 8 Sambas, no problem.

I'm thinking something with the choke system since it was soon after start up. Hmmmm, do modern engine management systems still have a choke mode?

 

Engine surge is a real thing. Search for it in the repair manual for causes.

However, the fact that it happens while you're just sitting there idling suggests it may be software related. There have been law suits filed against Jaguar for this issue (X-Type, S-Type, XJ).

Try coming to a stop in neutral and see if the engine surges while in neutral.

Only thing I can think of would be a faulty ECM, Throttle body, or harness.

 

 

You said you keep it in sport mode most of the time, does it also happen in non-sport mode?
Just wondering, as I get a pronounced surge as the throttle blip while coming to a stop and it is down shifting. Could be a software issue where you are getting a delayed blip, or maybe it’s blipping while stopped as it drops into 1st gear?

 

Donknow, it's only happened twice almost a year apart and I've had the car since mid '17.

I'll check the neutral to stop first.

 

Actually I did have this happen on my car as well but I just attributed to glitch because of ECU reprogramming. Scary when it happens

 

Your heel was on the bottom of the throttle.
Sorry, it isn't a mystery.
The pedals were placed poorly by Jaguar.

 

hmmm, fits me perfectly

 

Cee Jay, why do you persist? He wrote his foot had been on brake for a few seconds. I agree sometimes (often) it's the simple things, but doesn't sound like it here.

Maybe the cruise control or ACC, that's the only systems that take over and overrule the accelerator input, right?

 

and sometimes I swear she has a mind of her own and just to mess with me, changes location in the parking lot.

 

An air leak could just about cause it - well, not full throttle but the effect of some extra throttle. Go hunting for leaks. Look at fuel trims - especially when the car misbehaves.

The idea that it's software just doesn't hold water bearing in mind the many thousands of cars over decades with no problems.

 

07 NA 4.2: I got a consistently repeatable rapid increase to 3K only on cold startup. Found that I had not properly secured the intake hose to the throttle body -- a massive vacuum leak. If I had put it in gear as soon as I started, it would have been driven forward or back quite suddenly. Properly securing it and tightening it down corrected the problem.

 

this still does not make sense. cold startup is 1500 rpm for a few seconds in my car, until i step on the brake again, before even reaching for the shifter. the vacuum leak forces the engine to rev higher during this procedure, yes, makes sense.

so how does a vacuum leak tell the computer that there is positive user input on the accelerator pedal and to engage the transmission, all while still holding the brake pedal down, which you'll need to do to shift at all? you're in neutral.

 

In park, of course -- but neutral is assumed. Didn't touch anything but the brake pedal, since it has to be pressed to engage the starter. When engine started, removed my foot from the brake. Behaved exactly like a normal cold start, up to 1-1.5 K or so. Then it kept on going instead of dropping back down. As it reached 3k, I always shut off the ignition. Didn't want to let it wind any higher. Clearly there was a problem and I wanted to mitigate the effect.

After a few seconds, I started it again, and it behaved normally. Why did it do this when the intake tube was partly off the throttle body? Not a clue. The only thing happening at that point in a cold start is the EGR sequence, as well as the AIR sequence. Maybe they were involved. In any case, as I said, correcting the air leak problem fixed the effect. Never had it again once the intake tube was correctly attached to the TB.

 

EGR yeah specifically EVAP purge. i wonder if it's possible that the canister has fuel in it, or, if there is some kind of restriction causing a venturi effect; it's siphoning fuel out of the tank via the canister.

 

All this talk of revving engines and acceleration is getting me hot and bothered.
Happy Easter All! I going for a drive in the sunshine.