First time since I bought the XK in December, I put the accelerator to the floor just to see what it could do. I was entering the freeway off of a cloverleaf. It downshifted and screamed to 6000 rpm within 2 seconds, and I immediately let off. It did NOT upshift immediately. It scared me that it took a full 2 or 3 seconds to upshift to the next gear (5th maybe?), and then another 2 seconds to get to 6th. I was doing nearly 70mph. It should have upshifted immediately upon release of the accelerator, right?

Any ideas? I'm not throwing any codes.

 

Mine doesn't, it holds the gear for a bit under hard acceleration. Why did it scare you? Are you saying it kept accelerating even with your foot off the gas?

Normal operation will be the engine brakes for you regardless of shift if you take your foot of the gas. The gear you are in is no correlation to your speed, just how much the engine is revving to be at that speed. You should see how it operates in the S setting of the tranny (Sport), when I first put that in it never shifts down when first engaged. Just screaming down the road.

 

You caught it between shifts and confused it for a moment. These cars learn your driving style and anticipate your control. It thought you wanted to Go Fast, but then letting off sort of Made It MAD.
I burned up an old Ford AOD in a Thunderbird I had, went to pass a long line of cars on a highway and floored it. A downshift from OD to third and then I saw the Highway Patrol so I let off at about 90 MPH, but then I noticed it was NOT a Patrol car so I floored it again but it stayed in OD that time and PLOOEY, the Overdrive part of the AOD took a pooh. I still had about 900 miles to my mid-round-trip destination... made about 18 MPG instead of the 28 or so I should have. I had a shop replace the whole shebang before the return trip for $3500. I was always careful after that. AODs are/were junk.
Sorry for the rambling.

 

HAHAHAHA.... because my 1999 Ford Explorer V8 would have IMMEDIATELY upshifted. And my wife's 2005 Dodge Grand Caravan. And my daughters' cars, and my son's car, and every other automatic transmission vehicle I have ever owned and/or driven.

It scared me because this is my wife's new car, and she was in the passenger seat, and she turned to me and said something like "you BETTER not blow up my engine!"

Seriously, if a handful of XK drivers respond to me and tell me this is perfectly normal, I will feel much better. Otherwise, I question weather or not I have solenoid issues in the tranny.

 

"...this is perfectly normal"
with ONE caveat....
If you are in SPORT mode AND and paddle shifting, the transmission will STAY in whatever gear you select and keep bouncing off the rev limiter.
BUT, if you are in SPORT and HAVEN'T used the paddles, it will stay in SPORT AUTO and shift when it should. You'll just be in a gear or two lower than you'd think, to keep the revs up for when you DO mash the skinny.

 

At 70 MPH with full throttle, you were probably right near the two-three shift. A tiny pedal lift and the shift would have happened. Abrupt pedal actuation, either up or down, is not really necessary in your car, other than for a quick launch.

 

Gotcha, no worries, perhaps the word "concerned" would be appropriate. Saying "scared" makes it sound like a situation that is dangerous!

This car wants to be a sports car, so it won't operate like your Caravan.

 

The ZF 6HP transmission in these cars is a "smart" transmission, it doesn't do things the way an old traditional automatic transmission does.

What the OP describes is the "gear hold" function, to make the trans shift up after a a short burst of full throttle, you need to press the accellerator again gently once you've backed off.

If you drive aggressively (like holding your foot flat to the floor) then it thinks "ok we're being aggro now" and it changes it's shift strategy accordingly.

Holding a gear when you back off provides instant engine braking, it also means you can get right back into the throttle again quickly without it having to shift, shift, shift to get into the right gear for more aggressive driving, it's anticipating you driving like a hooligan, because that's how it wants you to drive

Basically you let off too early at 6000rpm, the naturally aspirated engines rev a fair bit higher than that...

 

I agree this is intirely normal, the car's interpretation of sustained full throttle is you have finally become a hooligan, and Ye Ha it wants that to continue!!

Thats another reason I love my Jag, luxury one moment, Super Car the next !!

 

This ^^^

 

It'll avoid that, quite happily. (Just watch the speed - tickets can get expensive.)

 

+1 on Cee Jays comment. Albeit you were a bit concerned, the experience was perfectly normal….. got your heart a bit thumping

 

I called it the wrong thing, this feature is called "Fast Off" and you can see it described in the owners manual:



Fast-off: Activated when rapidly lifting-off the accelerator pedal and takes account of road
gradient. This feature inhibits up-shifts,
enhancing performance.