I have a 98 Blazer that has alight "woop woop" sound only really heard when slowing down from about 25 miles an hour. Two different reputable service stations could not diagnose the problem even though they heard the noise. I've had the front end completely repaired with Hub assemblies, bearings, pitman, idler arm, brakes, etc, and mechanically they find no problems with the front end. They also dismiss that the tires could be the issue. They suggest going to a chevy dealer shop who might have better diagnostic abilities. Any comments would be most welcome. (BTW, I just got finished having a new rebuilt engine installed due to major problems and aside from this noise, all seems perfect now.) thanks.

 

This could be abnormal wear on the tires. If you have saw toothing of the tread, it can cause a cyclic noise like this. The old tires on my Rainier were saw toothed quite badly and it sounded like I had a bad wheel bearing on the front. New tires and the noise is now gone.

One thing to try if you suspect the tires is to rotate the front tires to the back. If that helps, then it is the tires.