I've one of those problems that's tough to track down.

Under hardish (enough to cause transmission to shift down out of rpm range) acceleration my 2010 XFR has has a small miss. It occasionally seems to have a tiny miss at idle. To repeat the miss, I have to paddle shift to stay in 4th gear and accelerate hard trough 2800 to 3200 rpm (about 80 km/hr to 110). The sound comes across as a ticky sound, it arrives and leaves reliably over the rev range.

I'm curious if anyone else has solved a similar issue, it's pretty minor and a Jaguar specialist has advised that there are no codes that there's little we can do at this point unless it worsens to the point of something that isn't a goose chase to diagnose. The car has 104,000 km and hasn't had a 'tune-up' or any ignition of fuel system issues that required maintenance.

Possibilities from my reading around the internet:
1. Fuel pressure inadequate - nothing in the codes
2. MAF and equivalent sensors on the supercharger - nothing in the codes
3. Supercharger noise/early bearing issue?
4. Perhaps the exhaust bypass valve is in the early phase of opening, but the sound is very much a top end of engine sound and from the front of the car.
5. Water pump? I know they fail pretty frequently, this one was replaced at ~45,000 km 6 years ago.

Looking at dyno charts this is the period that engine is building to max torque, but not by any means the max torque range. I presume fuel demand is at its max, but not the peak requirement so given the lack of codes it doesn't seem fuel related.

This fall the weather is getting cooler, and it seems that when the engine is in warm-up and not fully up to temperature that the miss isn't happening. I can only assume that this is a result of the cooler state of the ignition system providing enough spark or energy to avoid the miss. It also seems reasonable that there's a much more complex ecu response going on that would be hard to figure out as a laymen.

Any ideas?

 

In my experience, those types of misses have always been ignition related. There's a lot of things that can cause a miss, but it's always been ignition for me.

 

You might look at OBD data such as fuel trims but also the other things in case something sticks out as odd.

I'd suspect the battery somewhat and after that a coil.

I think the OE diag tool can read misfire counts per cylinder in real time as you drive.