Helm Manuals..
The Helm manuals are very good, but they are HUGE! Include the info on every Buick for the year, all engines, all transmissions, all steering, etc., on loose pages. By the time you go through and take out all the stuff that doensn't apply you're left with less than four inches of book pages, but you have about 18" you don't need. You will have the wiring diagrams, the troubleshooting charts, and descriptions of all the major parts/components along with settings, like the values for "Low MAF Flow" (Code 34), or tlow MAT (Code 24)