should I be able to hold the liftpump plunger down with the truck idling?

 

Can't tell you, never had a reason to do so.

 

Bill you have never pushed on that plunger at all while truck was idling? I have gauges I know what my fuel pressure is, I was just wanting to know how stout the plunger should be under pressure. Like I said I know what my fuel pressure is but I CAN hold my LP plunger down completly at idle.

 

That's normal. The plunger and the pushrod driven by the camshaft are seperate mechanisms.
-john

 

on mine its hard to and you can feel it pulsate with the fuel cam