I just replaced the fuel pump and fuel filter last wknd. Today my wife told me the jag started to feel like it was choking at 50 mph when she mashed the gas. I got in and floored it good till about 50 mph and it felt to me like it was fighting (almost like needing to shift in a stick).

Any help would be appreciated. Sorry I can not give a better description,
Thanks guys

 

Does it run rough under lighter accel? Splutter at all?

 

Under 50 mph the acceleration is very smooth. If I just gradually press the gas pedal it is fine but when I put my foot on it to pass someone it started to sputter (hesitate). The only thing i did not do when I changed the fuel pump I left the plastic guards off the engine. I do not know if that would cause something but I figured I would mention it just incase. Thanks for the help and answers.

 

If you are talking about the little side covers, they would not affect anything. Under the hood while idling, is their any sound of sucking, like a vacuum leak. This would have less effect under hard acceleration, but need to check basics. How many miles on the car?
I would also look at the throttle body, take off the air boot and see if there is alot of carbon buildup. Also, look at cleaning the part load breather. It is the smaller hose on the drivers side of engine. Take off the hose and clean in the hole on cam cover. One size down from a 1/8 drill bit normally works fine. Or if you have an old antenna mast floating around, the narrow end of that.

 

Ok I know this is going to sound stupid, is it safe for the wife to drive or should we garage it for the meantime.

I did not check under the hood yet. I did replace the air filter when I replaced the fuel pump and fuel filter. It has 62K miles on it. When I get a chance this wknd I will look at all of these things. It sounds like stuff I can do just need a little help.

Any good places to look to find a schematic to show me all of the parts of where things should be? My buddy promoted me to tree shed meachanic lol

I have belonged to different sites for my Nissan Titan and Mustang Cobra but you guys are by far the most helpful and honest with things.

 

look at both PCV plastic hoses going to each cam cover.. right side will be big. make sure all is plugged in when changing the air filter.. and the little one on the left.. you can pop off carefully and with small drill bit.. make sure it doesnt fall in.. see if the air way into the cam cover is clear with the drill bit... .. when you cahnged the fuel pump.. did you make sure the feed hose in the tank was on all they way.?

 

Yup the hoses are all in. I will check everything else in the morning when i have some light.

 

All things checked out. Apon further review it only does it when the sport mode is engaged. Any ideas?

 

Dont engage sport mode.

 

Is this something I need to worry about?

 

Hi from Abu Dhabi, had similar problem last month with my XJR 2004, 30.000km ( 18.750 miles)
Took to workshop here, and was the throttle body they said, acc. to computer testing.Got a new one same day installed, and uffffffff gyes, car is like new!! Just came out of the factory.Payed 4.500 Dirhams, equal USD: 1230.
Don"t hesitate to put new one, otherwise is not a Jaguar anymore!

 

Newjagowner said he was able to change the fuel pump without removing his tank. I am having trouble believing that is possible without kinking the fuel feed and return lines that connect to it, and perhaps this is causing a fuel starvation and his current symptoms. It also suggests that he may not have completely drained his tank and made sure it wasn't full of crud that is nowpartially restricting his pickup filter.

I replaced a fuel pump in a '95 XJ6 last week, and that car had similar driveability faults. The engine idled fine, and would run OK if you "soft-pedaled" it when accelerating. Fell flat on it's face, even popped back through the intake from lean running, on hard acceleration. The fuel pressure gauge showed why: it was dropping to 20 PSI at WOT. The inside of the tank was pretty clean, but the pump pickup screen was full of debris and probably the only cause of the starvation. I wasn't going to bet $150.00 that the pump was perfect and risk having to do the job again, so I installed a new one and the car left running perfectly.

While under the car, I had a look to see if there was enough manouverability of the fuel lines to permit moving the tank far enough back to remove the evaporative loss flange. I don't think it can be done without damaging the fuel lines. If you are changing an in-tank fuel pump, and XJ40, late XJS,X300, and X308 are all basically the same, you'd best disconnect the fuel lines and remove the tank if you want to make sure the job is done properly.