Pete,
Welcome to our world. If it starts and won't idle, it sounds like fuel. Search this site for fuel pump and mixture issues. There are plenty of posts. "ja17" is Joe Alexander, who has posted a great deal of good procedures for chasing these problems down. Do some homework and follw his advice meticulously. You could have something as simple as a clogged fuel filter or return line. As Joe has suggested, start at the electric pump and work forward. If you eliminate fuel supply, then start checking the linkages and the FI pump mixture.
Ray
'68 280SL 4-spd Coupe