Hi all,

Any help appreciated please:

Under hard acceleration my 1999 4.0 XKR misfires and stutters at approx' 3000rpm, effectively cutting my top speed to around 90mph.
It doesn't get through it, clearing the other side, it hovers around 90mph top wack.
This is in "drive", and it makes no difference if I am in standard mode or sport.
If I change gears manually via the J gate however, it charges right up to the rev limiter in second.....
I can't say if third and fourth misfire using the manual gearchange, because on the roads I tested it on it wouldn't have been particularly clever to go any faster!!
But in drive, it definitely misfires.

Anybody else come across this? No error codes showing.......

Thanks, Martin (UK)

 

bump......

 

Your XKR has two fuel pumps. It sounds as if one may not be functioning.

 

Hi I had the same problem exactly. I swapped the generic MAF sensor out with an original Jag one. The problem is now fixed permanently. The Jag one has 2 tiny sensore, one for high load. The cheap chinese knock of doesn't.

 

the second sensor inside the MAF is for air temperature, not high load.

That said, the generic sensors for the 4.0 XKR’s leave a lot to be desired. I could never get any aftermarket MAF sensor to properly adjust the trim numbers, and I tried 3 different ones. In desperation I bought the pricey Jaguar part from a dealer. End of trim number issues.

The MAF for the XKR’s is not the same as the one for the XK8’s. Many different manufacturers use the XK8 type, and the price is reasonable. On the other hand, only the XJR uses the MAF sensor used by the XKR, as far as my research found out, and it seems there is something special about the unit that the aftermarket types do not replicate.

Z