top sags to one side
 

the top section my 1999 hi-low sags down on the left side, how can I fix it and is it something to worry about?

The cables can be adjusted to level it out but it's a sign the left side cables have been stretched. I think it's worth just adjusting them and running with it. There is a guide on here somewhere but in mine I just put a floor jack with a piece of 2x4 under the low side when lifted and jacked it level then tightened the 2 low side cables which are all in between the drivers side wheels.

Thank you very much!

Worked like a charm! Thanks a bunch!