Cold start-up noise and gas mileage

[phillypoet313]

Just bought a 2002 trailblazer ls with i6 4.2, I have a few questions...if any member can help.

1) How to reduce the valve tap noise associated with these motors that occurs in the (cold) morning? I've changed the oil to mobil 1 synthetic and a premium filter.

2) How to get better gas mileage? I changed the plugs, air/fuel filter and checked tire pressure.

3) I have 100,000 miles, should I change oil weight/brand?

 

[Wooluf1952]

Just bought a 2002 trailblazer ls with i6 4.2, I have a few questions...if any member can help.

1) How to reduce the valve tap noise associated with these motors that occurs in the (cold) morning? I've changed the oil to mobil 1 synthetic and a premium filter.

2) How to get better gas mileage? I changed the plugs, air/fuel filter and checked tire pressure.

3) I have 100,000 miles, should I change oil weight/brand?

#1) IDK if there is a way.
#2) What rear gears do you have? Do you have 4x4? Have you changed the diffs to synthetic?
#3) If you're not using oil, stay with the 5w-30.