They do, called the 'Altitude Compensating Device'. I believe it only really helps with idle at different altitudes.
Greg has a little information on it on his L-Jet write up;
http://www.hiperformancestore.com/Ljetronic.htm - Step 10
ROCK ON
R~R
Greg has a little information on it on his L-Jet write up;
http://www.hiperformancestore.com/Ljetronic.htm - Step 10
ROCK ON
R~R