1999 Suburban 5.7 auto. If it sits more than 2-3 days, when I go to crank it, it wants to lock up. I am going though starters and flywheels like crazy. But if I run it everyday it cranks and runs just fine. I have replaced plugs, wires, cap, rotor, fuel pump, and fuel filter. When I take out the plugs it cranks fine and no fluid is coming out of the cylinders.

 

I wonder if it's a lubrication problem or bearings?
How many miles?

 

When it runs it runs fine. No knocking or anything. Then when it sits for a couple days it will turn over a few times then it will lock up. Do you think it could be a leaking injector causing it to hydraulic lock.