2000 trailblazer knock
 

I have a Trailblazer, the old one with the Blazer style. Vortec v6 160,000 miles. When I start it the engine ticks after driving about 20 minutes it stops ticking, someone told me it could be a lifter. I run regular unleaded and have the oil changed every 2500 miles instead of 3,000. There is no loss in performance during the ticking the oil pressure says in normal range. Any help would be great!

i would say that your friend is correct. it is something in the valve train. either a lifter, push rod, or rocker arm. could be something that just is out of adjustment. or it could be that a push rod is slightly clogged and isnt letting oil up it right after you start it. if you dont hammer on it, you could probably put another 150,xxx miles on it before it gives you any actual trouble. but its hard to say. for now, i personally wouldnt worry about it unless it gets worse in short order.

I am having it tuned up as well as having the lifters looked at to see if one is slugged up or just loose. Hopefully it's just dirty, this is a great truck and I can't afford to replace anything more then the lifters.