I have a 2002 Blazer 4.3L engine with 117,000 miles

I'm hoping to get some suggestions about what could be causing a ticking noise I've started hearing coming from engine recently.
It seems to stop once I get the engine running at normal temp.
Over the last year I've replaced water pump, radiator and most recently fuel pump and fuel filter (after the blazer died in traffic with no warning)
It's due for an oil change in another 100 miles and will be changing it this weekend.
I've also noticed since the fuel pump replacement a month ago that my gas mileage has gotten worse.

 

Ticking noise from the engine can be caused by lifters/valves or a bad bearing on one of the engine pulleys.

 

I agree that it sounds like it might be an upper engine lubrication issue. Try doing a treatment with Auto-Rx and/or using a 10W30 oil if you are not already.

 

Last weekend I ran into this problem on a '97 4.3L. Read many posts pertaining 2 this. u can try the engine flush method with the oil. We replaced 12 lifters that were pounding away but it still makes a bit of a clacking noise. Did all work as manual & experience would / should have panned out. Got timing dead on.