JGC 4.0 - Stalling in reverse

Help needed please!!
Over the last week, my 1999 JGC has started stalling when shifting into reverse. When I select reverse, with my foot on the brake no problem, it only stalls when I apply any pressure to the accelerator. After it has stalled in reverse, it is sometimes difficult to get it idling OK in Drive without stalling, always starts with the first turn of the key, but just dies.
Regards,:runaround:

Has the local temperature changed?

How many miles?

Any other symptoms?

How long has it been since you put in a fresh set of spark plugs?

Thanks for your reply,
to answer your questions:
The outside temperature has only dropped a couple of degrees over the last few weeks.
it has covered 142k.
the only other symptoms are it is sometimes a bit sluggish through the gears.
and most embarrassing of all is i am not sure about the spark plugs, so i will be changing them this weekend!!
Regards,

Post back after you put in the new plugs -- just a thought in addition; does it use any coolant?

I have just managed to replace the plugs. it now runs much better, but still cuts out when I select reverse!! with regards to the coolant, I replaced the radiator about 4 months ago, and since then i have lost no coolant. but just in case, i flushed the system today, but still cutting out.
Regards,