Thanks. Someone on another forum suggested a clogged cooler. What gets me is that it seems to function fine till it warms up. I did unplug the solenoid and the problem persisted. Also, the problem appears before the solenoid should ever be engaging.

So, now you have me thinking the problem might be in the cooler. If it is, and not in the lines, I should be able to just loop the hose and bypass the cooler temporarily and see if the problem goes away, correct?