I am new to this. The DBC(dead bottom center) is when the piston is at the bottom of the engine? Do you need to take the air filter off to this? Does the air filter just slide off by pulling on the neck of it, then you just slide it back on?

I've been looking all over the Mgt 8.0 manual for the location of the needles, but I believe the engine in the manual is not the same as in the truck. I know where the hsn is but where is the lsn and the idle screw?