In modern computer controled fuel injected cars plugs last as long as 100,000 miles. Unleaded fuel and HEI ignition help this some too. In the days when our cars were rolling onto the showroom floor and into garages and driveways for the first time plugs were changed every 12,000 miles. If you have 10,000 - 20,000 miles on your current plugs I think they have lived a usefull life span and would recomend replacing them. Easier starts, smoother idle and better gas mileage should be the most noticable. If you did back to back track runs, your times should show a slight improvment with the new plugs. Unless they are really bad I don't think you'll feel a seat of the pants improvement...
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
"Don't take life so serious, you won't get out alive..."