Hi all, my XKR started spluttering in the hot weather last summer, with the transmission cutting out also making the car crawl. The car has been fine all winter, and now i am good on cold days, the fault returns when temps hit 90ish. Any ideas?

 

Any codes showing?

 

Opps, sorry should have said that. No codes.

 

It may just be a coincidence about the weather. The "R" cars have 2 fuel pumps. I have seen where one goes out and the car will still run but falls on its face (You should always replace both, even when one goes out). I would check the fuel pressure.

Cheers

 

If you have a 4.2 it only has one fuel pump.

 

Stumpy. You are correct about that. Good catch.

Cheers.

 

You may have a bad intercooler pump (there is not error light / code for this) which can lead to performance issues. Please post your model year and we'll know if it's 4.0 or 4.2 Also as above any codes or messages you maybe seeing. You can 'test' the pump if it's spinning, with the car off and listening near the air box (the pump is just below it) have someone turn the key to position 2 (not starting it) and listen, you should hear the pump spinning, you may also want to check the fuse to this first if it's not. There are a number of threads here on replacing it if required.

 

The symptoms for the intercooler pump are usually pinking/pre-ignition when under load/power and fully warmed up. It does not cause poor idle or running under light throttle or transmission problems.
It is always worth checking the pump is running, as jamdmyers says, because it is a common failure.