I was going from one highway to another, the exit drops to the left, well half way down the RPM's just dropped like I was running out of gas (had 1/4 tank) and then going down another hill, car started acting like it was starving for fuel. Filled up the car and next day, no problem.
Do you have to keep these FREAKIN cars filled or near full??

Yesterday I was driving home on the interstate (full tank), I put the pedal down (full throttle) and after a second (normal fo rmy car) it started taking off. I let off the throttle just a fraction and then the engine started dropping RPM's and then revving back up and then dropping and then revving, did this about 4 times before I let off the gas almost completely, the car then shifted back into 4th and never acted up again, though I never tried to repeat the scenerio. Was not sure if it was caused by a malfunctioning sensor or if maybe the transmission just would not shift.
When I am on the throttle, car always seems hesitent to up shift.
I have no codes, so I am wondering if this is a TPS or MAF sensor just not reading correctly at WOT.

 

Does your OBDII reader have a monitor capability?

You may need to monitor the engine parameters in real time (fuel trims, O2, air, throttle, etc,) to diagnose the problem.

 

A local restaurant has a sign that I have always enjoyed: 'You do not have to be crazy to work here . . . we will train you'. That could probably be modified to apply to Jaguar ownership.

These cars were really state of the electronic arts when designed in the mid '90's. The XK8 shown in the '96 European car shows really only had only minor and slowly evolving updates over the years.

Without OBDII codes you are going to sneak up on all the things it could be. What you describe could well be associated with the throttle body electronics and there are a number of discussions on cleaning/replacing the connectors there. Another issue to pursue is fuel pressure/fuel filter/injectors that are not reported well via codes.

. . . or you could have gotten a bad tank of gas.

Good luck, keep us posted.

 

I agree with Test Point's thought of some bad fuel. So let's explore that idea for a second...

When you parked your car overnight, did you park on a hill, or was it on level ground? Here's why I'm asking: I got a tank of bad fuel a while back. The symptoms were similar to your's, except my engine completely died and I coasted to the side of the road and pulled off onto the shoulder. I cranked it to try to restart it, but it wouldn't restart. I tried every few minutes and after about ten minutes it suddenly restarted. A half hour later the cycle repeated itself. Long story short, when I pulled onto the shoulder the car was leaning quite a bit to the right. Water is heavier than gasoline, so the water had settled to the bottom of the tank where it was getting drawn into the fuel pump. When I parked on the shoulder, the water would shift to one side of the fuel tank which would allow the fuel pump to start drawing in fuel rather than water. However, it took a little while for the water in the fuel line to work its way through and allow the fuel to get back to the injectors.

If you got some water in your fuel but left the car parked on level ground, then the water would have settled to the bottom of the tank right where it gets sucked into the pump. Your car would have started, but within a minute or two it would have started running rough and possibly died. But if you parked on a slope, the water would have settled on one edge of the tank and then gotten sloshed around as you started moving. Then, as you drove stead down the freeway it would have worked its way back to the low point near the pickup to the fuel pump, and then you would have experienced the problems you described.

The easy thing to try is to buy a bottle of HEAT, pour it into the fuel tank, then fill up. The HEAT allows the water to dissolve into the rest of the fuel, which means that the fuel works it way through the engine a little at a time, rather than in big gulps.

 

I would explore the possibility that your fuel filter is plugged to the point that the pump is going in and out due to high current draw,or the pump is just giving up or the fuel regulator is going out.. none of this stuff will throw a code.

 

I meant to mention to the maintenance folks out there that not changing fuel filters often enough can put a constant load on the pump that overheats it and gives it a short life. The $80 XKR filter makes me think twice, but I bite the bullet and change it.

 

I think, but am not sure, this could be because of your driving habits.

At one point (when I just got my car with 31k miles) it had a habit of upshifting many times when I didn't want it to. I kept driving like I wanted it to and eventually it stopped up-shifting so much and now I can rev it up quick, let go of the throttle without having it upshift unless I give another touch to the pedal.

I'm wondering if a hard-reset would cause the unit to relearn?

/pureconjecture

 

I thought modern performance transmissions would remap themselves according to the drivers habits over a couple of days?

They will also remap to lower RPM shift points if you take it easy for a couple of days so you have to be fairly consistent to re-map.

My V70R and the XKR did this but then they both have Sport settings for the transmission.

Good luck if it is a fuel/filter/pump issue....those can be frustrating to work out.

cheers,

jj

 

Part 2:
Still no codes, but I have localized when the problems start.
I can hit full throttle anytime the car is in 1st or 2nd and no problems, if the car is in 3rd or 4th, car will rev for a second than cutoff and then rev for sec and will do this till I let off the gas below 75% of WOT. I am starting to believe I have a tranny issue or atleast an interface issue between the tranny and engine management systems.

Anybody ever run across a problem like this?

 

send me the 70 Cuda and Ill tell you what I would look at and do to fix it.... WTF Im tired of FREE advise, I want some ching

 

Randy, I am wondering how you have a '70 "Dodge" Cuda?

Dodge made the Challenger (still does) and Plymouth made the 'Cuda, which was a version of the Barracuda. I had a 1968 Barracuda and then a 1972 340 Duster (Dodge's version was called the Demon). The Duster and the Demon were essentially the same car, but the Barracuda and the Challenger were very similar but the Challenger had a slightly longer wheelbase and was a bit heavier. I grew up going to the drag races and while the Barracuda had a great deal of success there, the Challenger did not, as it was at the upper end of the weight for its class and the longer wheelbase meant that it did not transfer the weight to the rear wheels as well.

I saw Sox and Martin at the track and even went to a meet and greet that they had at a Plymouth dealership in New Orleans.

There was a local racer who was a National Record Holder in Super Stock, driving a B/SA 1964 Plymouth Belvedere with the 426 Hemi. My relatives owned the Drag Strip so I had some pretty good access in the pits. I was there the day that he brought in his '68 426 Hemi Barracuda that Plymouth made only about 50 of to qualify for Super Stock. You know, the ones with the plexiglass windows that you put up with a strap and no seats except for the racing seat.

He took that thing off of the trailer, straight from the factory (he had gotten it the day before) and he was running in the mid 10's after a few runs.

This is the Sox and Martin car that I saw (or one like it, they probably had a few later bought the same year Barracuda)

Sox & Martin 1968 Cuda Vs. Motown Missile 1971 Challenger - YouTube

This is his 70 'Cuda
1970 Sox & Martin Pro Stock Hemi Cuda 1/4 Mile Pass 2 - YouTube



I am a Mopar man from way back, and when I saw "Dodge Cuda" I just have to ask the question.

Thanks.

 

First of all I admit that I just skimmed over most all the posts sot if I do not understand the situation please let me know. This car is an electrical nightmare and yes as already indicated it was ahead of it time. What you need to know and understand is that the engine, trans and a bunch of other stuff must work together to work properly. If the engine or trans is not operating properly the other will suffer. The comment earlier to replace the filter is not a bad idea and I think you can get an aftermarket filter for less. Chances are that Jaguar did not make that filter it was outsourced.

I would first have the battery checked, then pull the ground lead from the battery and turn your lights on to clear the system of any residual power. This will clear the memory and begin a learning sequence for the engine and trans. With the lead off I would check both terminals for a good clean connection. I would then add a fuel additive BG44K and drive the car. The additives will clean the fuel injectors and valves and that should get you started. Water in the tank is a possibility so if you add something to the fuel for that do not add the BG44k until that tank of fuel has been replenished. This is a long shot but you’re my car has a TSB on the throttle body plugs 303-58, what it means is that the plugs are not compatible and should be replaced. This link will help jaguar throttle body plug Yes in most cases you will get a code but not all the time, it is worth checking out.

 

Brutal,
It is Xmas time, a time for giving!

 

Where do you see 70 Dodge Cuda, it just says 70 Cuda. Think your eyesight is gone or your brain.

 

Trying again -

Car goes to WOT throttle fine in 1st and 2nd gear, i.e. no fuel problems.

It only happens when car is in 3rd or 4th gear.

 

My sister got braces on her teeth. Instead, I got a 71 Dodge Challenger 383--red with black vinyl top. Good looking, great running, bad stopping. 18 mpg was much better than I getting on my 64 Valiant.

Looking back, the body and interior were very poorly engineered. I constantly had to put stop switches in the windshield wiper motor. Rear end needed re-shimmed and hummed badly after 100K miles. Probably worst car (of my 50+ new cars) I ever had.

Boy, do I miss that car.

Yea, Jaguars XK's were 10 years ahead of their time, and the subcontractors (Japanese) designing the 17 or so modules on the car did a very poor job. It's just a shame that many modules are dependent on each other and the mechanical condition of the cars. Now, every auto made (since 2008) in the world is CAN/BUS equipped. It's the electronics that let smaller, more efficient engines put out incredible horsepower. Fortunately, they've now got most of the bugs out of the electronic modules, etc. We're stuck with the eccentricities of a Jaguar electronics. But what else would you expect from a Jag?

 

HAHAHAHA!!! That's funny, randy. You edited it now to say Plymouth Barracuda and now try to pretend that I was the one who was seeing something.

OK, play your little games, it's OK. Hope you get your problem fixed.

 

I saw just Cuda before anyone said anything......

 

I wonder if your problem is related to the kickdown switch. It would be getting activated at WOT.

 

The kickdown switch is on the engine side or the tranny?