I'm not quite sure why, or if this is a normal issue with jags - but there isn't really a smooth transition when I press on the gas pedal. It acts more jumpy than anything. (It also feels like I have to press down just a little more from the start in order for it to get going.. almost like there's a small gap from the pedals resting point until it finally kicks in)

I hope I explained myself well, and thanks for helping me out.

 

my car does that when I pull away from a stop. If, I try real hard, i can avoid the leap but i end up with a queue of traffic behind me.

whenever I see an X downtown in Toronto I always watch for the motion of the car as it pulls away from a standstill and almost always, I see the leap.

I was told it is down to the "fly by wire" nature of the electronic throttle - they are just programmed that way. Three years in, I've got to quite like it!!

 

I just bought a 2004 x, 3.0 auto. It had a very harsh tip in. I replaced the pcv, fuel filter and cleaned the mass air and it virtually eliminated the "leap".

 

To me, it almost comes across like turbo lag. My last car was a Saab 9-5 with a 2.3t. The feeling is similar. Odd.

 

Keep in mind that the gas pedal because it is fly by wire has a certain dead spot to it to allow the computer to be able to see the pedal in the full return position. This is done to ensure the throttle body goes full closed and does not keep the engine under some amount of load (ie, thinking you are keeping your foot on the gas).

If the Jag is like other Fords, what you can do is to take a multimeter and connect it to the throttle position sensor and then you can loosen the bolts. From there, you can twist the TPS until the multimeter reads 0.99 VDC. Going to 1.00 or above makes the computer think the throttlebody is open. This will help with the response of the engine.