motor issues

[onus]

we have a problem with our jaguars i believe.

we can run our motors backwards but not forward.

push the back button they run nicely
push the forward button they grind and stutter along.

if we switch the polarity, they will run happily in the opposite direction of before but sutter in the other direction again...

so ive become convinced its in the programing.

all imput and advice appreciated.

new to the whole programing concept. so im a complete novice, just fyi.