XJR X308 coughing under hard acceleration

[Zippyworld]

Hello,

Does anyone know where to start with a coughing / blowing issue, the car not me ?

When I put my foot flat down or nearly flat down she’s really not happy, it feels like a misfire and blowing off through the exhaust, its the only way I can describe it.

At 5500 revs all is fine, its just under load. In all gears.

Could really do with some advice on this one please, any ideas ?

Thanks

[Zippyworld]

This is going one step further now, thecarhas shown a fault code P1601. Incorrect control module.

There have been no modules replaced or tampered with.

Anyone shed some light on this please ?

I am changing plugs and coilsas a matter of routine and elimination.

[Zippyworld]

Thankyou for the input, fuel filter had been changed and made little difference. Cats are good too.
Its starting to look a lot like one of the fuel pumps.
There is a new fuel pump going on the car this week.

Will let you know the outcome.

[Zippyworld]

Finally got to the bottom of this.

Two things, the first was a knackered fuel pump.

The secondary issue was a real head scratcher, it turns out that the Lucas coils ( which I thought were OEM ) well one of them was faulty, despite being brand new.
It didn’t show up on the dash because it was only losing a spark at full throttle.

The final repair was replacing with used genuine coils from a breaker, too pricey from Jag.

The car had a used pulley replaced on both the waterpump and AC unit. It also got a new alternator and it still bloody squeals when started from cold.....!