GM Service Manual Online
For 1990-2009 cars only
  1. Check the tire pressure.
  2. Adjust the tire pressure as noted on the tire placard.
  3. Road test the vehicle to verify the problem.
  4. Perform the following steps to test each strut:
  5. 4.1. Test each strut in turn by quickly pushing down, then lifting up the corner of the bumper nearest the strut being checked using the same amount of effort on each test.
    4.2. Note the resistance on compression and rebound on each test. Most resistance should be noted on the rebound stroke.
    4.3. Compare the resistance with a similar vehicle having acceptable ride quality. Both vehicles should provide the same feeling of resistance.
    4.4. Replace the struts as a pair if there is a substantial difference between the struts of the two vehicles or if they rebound excessively.