This is a fairly common occurence. If you carry some tools in the car you can usually fix the cable in about 10 minutes. It commonly breaks off a short piece at the back end where the cable flexes at the input trunion. Loosen the cable at the front end, pull it back a little at the inut end, and re-string it through the input trunion fitting. Clip a small vice grip on the broken end of the cable, then readjust the output end, and you're on your way.

If you drive a lot, carry a spare throttle cable with the tool kit, as they tend to break at 15,000 to 20,000 miles. I have been scratching my head over this problem for years, but so far it doesn't seem serious enough to bother fixing. One cure would be to install an anti-friction bearing on the input trunion mounting so it can rotate freely in the arm to prevent the cable from flexing. Another fix might be to install a sliding guide on the trunion to maintain the orientation while the input arm swings.

If anyone has a better idea for an easy fix, do tell.

If the cable breaks at the output trunion, you will need a little extra length on that end to reconnect it. Pull the outer jacket forward until the inner cable disappears well inside out of the way. Cut 1/2 to 3/4 inch from the end of the outer jacket. Then put the outer jacket back into the bulkhed fitting, push the inner cable forward to expose the output end, and reconnect it. This may work once and still have enough cable length to be servicable, but don't push your luck for a second time. At your earliest convenience, order a new throttle cable for a spare.