Excessive Exhaust Emissions (Odors)
Fig. 1 Service Parts Application Chart:
*** THIS PROCEDURE HAS BEEN UPDATED BY TSB # 86-149, dated 9/86
Some 1986-88 4.3L engines may have an exhaust odor described as a rotten egg smell or sulfur smell after towing a trailer or returning to idle following sustained highway driving.
Figure 1 list's the appropriate service parts to fix the problem.