Kinda reminds me of my problem. Only difference is mine is very random. So random that i cant track the noise down. https://blazerforum.com/forum/2nd-ge...-lifter-61135/

still in the process of piecing my blazer back together however I have come to the conclusion that the problem may have been a stretched out timing chain which when pulled apart my chain was extremely loose dont have truck fully together yet but that may have been my problem once I drive it ill let you all know if that fixed my problem

well installed the new timing chain and gear and still same problem will still update on what the REAL issue is if I don't give up and sell the truck.

did u replace the lifters?

ive done all the above except timing chain.new lifters,new distrbuter (on way) .checked EGR.it rattles. new intake gaskets etc ...check timing ( a timing light will not work). have to hook up to a computer to check and adjust or get lucky and loosen dist. and try doing a manual adjustment. i have read on here that it can be done . look under diagnostic codes P1345. have not tried the spark plugs but i will

Thought I would finally give an update it was a lower engine noise probably a spun bearing didn't have time to repair or replace the engine nor could I afford to have someone do it for me so I sold the truck thanks for the help.