I've just realised this is only my 2nd post and I'm onto my 3rd Jag now.

I have a small issue I can't find any solution to having searched the internet for weeks.
3.0 X-type Auto 2002. For the first half inch of accelerator pedal travel nothing happens. If I keep pressing very slowly the revs go from idle to 1200 rpm and nothing in between. If I ease of very slowly the revs will slowly drop though.

I've tested all the voltages and resistance on the TPS, throttle input wires and the accelerator pedal and they are all within specs. I even changed the accelerator pedal just in case but there is no change in the way it behaves.
The voltage from the pedal doesn't change for the first 1/4 inch but then it does change slowly, same on both pedals I've tried.

Diagnostics show no codes, and all fuel trims are correct. No vacuum leaks that I can find anywhere, I've sprayed propane gas around every pipe.

I had a 3.0 S-type that didn't behave like this.

Is this normal behaviour for the X-type?
Its very frustrating pulling away at junctions.

 

Not normal. As this and most newer cars are "drive by wire", i.e. Not cable actuated, the r.p.m. increase is determined by electronics. My bet is the throttle position sensor is buggered some. I'm attaching a video for a different problem, but shows the tps taken apart, "repaired" and reinstallation.

 

Btw, I would also very lightly have buffed up the contact plate on the "lid".

 

There's also the tps out on the right side (left if in front of car looking into bay) of maf area. That could be acting up as well.

 

I've seen that video before, but I've changed the accelerator pedal and its still got the same throttle delay. Its not the TPS as the throttle isn't receiving any different voltage for the start of the pedal press. The link between the pedal and throttle is the ECU so its not telling the throttle to move until the pedal is pushed down further.