Hi Ken
I've been watching and reading this thread with great interest and I've got to admire and take my hat off to you for your persistence. Don't give up your nearly there.
Have you used interrupt's in your code ?
If you have not may be the pic cannot proeccess the comamnds quick enough to repsoned. having watching some other video clips they seem to responed really quickly travelling at high speed.
I was thinking of trying my Nitro car but I think that would be to fast.